The Psi Overhaul in Cliffnotes:

01 - The Psi Lab no longer exists.
02 - The Psi Operative no longer exists.
03 - There are new Psi Amps now that can be used by any class instead of their regular secondary weapon.
04 - All psi amps give access to certain Psi Perks, all of them active skills.
05 - Using a psi perk caues feedback damage to the caster. This can be 2,4 or 8 damage, depending on the tier of the perk.
06 - To protect against feedback, you can wear a Psi Armor. Psi Predator Armor reduces the feedback damage by 50%. Psi Warden Armor reduces the feedback damage to zero.
07 - All psi armor also give passive perks like Fortress or Solace.
08 - Psi Armors and Psi Amps need to be built individually. This requires a healthy stock of Cores, Sectoid Corpses and Priest Corpses.
09 - Currently there are two lines of Psi Amps, both exist in 3 tiers. There is the Oppressor Amp which provides damaging psi abilities and the Dominator Amp which provides mindaltering abilities.
10 - Oppressor Amps require Sectoid corpses to build. Dominator Amps require Priest Corpses. Both require Cores.

More is to follow, but this is the initial implementation so far.
I plan on adding at least one more line of Amps (Savior Amps, for healing) and putting all these things into the loottables as rare drops.

<reserved for details... coming soon-ish.>

Intent behind the psi changes:

In vanilla, the Psi Operative is weird. You spend all your campaign with some soldiers you start to like and then these guys show up after training for weeks in a facility and are demigods.

Superlame.

By moving the psi perks onto equipment and making it available for everyone, you can use psi and still keep your crew.

It's also more balanced now because psi comes at a tradeoff - you will have to leave your secondary at home. And if you don't want to suffer feedback damage, you'll also have to use an armor with lower health and armor than the other armors on that tier.

The whole thing lets you decide how far you want to invest into Psi. All these things eat up Cores. While it seems expensive, the items can of course be passed around so they are almost squad upgrades. Just don't lose them in the field...

This is probably a bit quick and scattered but hopefully still helpful. I feel Psi OPs two main problems and solutions boil down to:

1. They're too powerful. Your proposed psi-armor fixes some of this. I'd even consider cutting down the health add by 1. Make them more glass cannons. The extra cost for building this armor individually is also a strong enough opportunity cost. I'd rather see the amp be in addition to the secondary weapon because losing abilities isn't fun. I'd rather see the opportunity cost come in other ways (money, AP to learn psi abilities, reduced stats elsewhere, greater fatigue at end of mission, etc). Nerf them without cutting the fun of using them when you get to use them.

2. Psi Ops "replace" soldiers you grow attached to. Superlame as you say. So the solution is to give existing soldiers Psi abilities in some way. Making them purely item driven diminishes the unique characters progression that ABB does so well. You know the saying - when everyone's a Psi Op, no one's a Psi Op.

Psi Op abilities might work best X-Men style - they get them early (with normal leveling), but they're uncontrollable and generally cause more harm than good (feedback damage or could also be feedback insanity/panic/etc). Psi Labs training and/or armor helps control this. During promotions, higher tiers offer psi abilities depending on previous promotion options (so if a soldier rolls a psi ability in Tier 2, but it's their first psi ability they get a Tier 1 psi ability instead). Psi abilities in tree add more opportunity cost in an interesting way IMO. Then make amps the improved version of abilities (Soul Steal, Statis Shield, Schism, etc). Adds some customization without putting all the power in items.

You do make some good points and mirror a couple of my own thoughts.

Ideally we would be able to get something similar to what has been done in EW/EU. Some people are just randomly Gifted and they get a completely standalone psi tree they can acccess after training. However, that's not something i can do, the UI and scripting for that is more than i can deliver.

So i decided to do the next best thing and make it equipment based, which ties nicely into the rest of ABB where soldier loadout is a bigger deal in general.

In ABB, humans aren't psionically active. But like with so many other things, we can use tools to make up for our shortcomings. I like this small but effective hook into a greater theme. Shen Senior would probably have something to say about that :)

The tradeoff between secondary weapon and amp is necessary for balancing, i think. i experimented with putting psi abilities on utility items, but i didn't like how they played. "Psi Grenades" don't do it for me. There are also technical limitations (progression in weapon damage, psi amp animations) that i didn't want to mess with. I think that the tradeoff and the opportunity cost (and the actual cost...) that comes with it prevents the "Everyone is a psiop" scenario.

Just straight adding psi perks to the perk roulette feels very unsatisfying to me. Makes them too mundane and takes away the players control over them. I am not able to build dependancies like the one you propose into the perk roulette, every soldier has to get a complete perk tree generated at squaddie.

There are a few things that i do want to explore further, though. Utility items could be a source for perks like Soulsteal or Schism that upgrade other psi abilities, for example.

Originally posted by DerBK:

Ideally we would be able to get something similar to what has been done in EW/EU. Some people are just randomly Gifted and they get a completely standalone psi tree they can acccess after training. However, that's not something i can do, the UI and scripting for that is more than i can deliver.

Have you checked out this mod? I don't know if there's anything you could borrow, or if you're interested in doing so, but it's pretty much EU psi ops exactly.

so basically agents and saboteurs will be the new psi ops. cant think of any other class id be willing to give up the secondary weapon (and the armor). maybe scouts too i guess. i assume this isnt an option for faction units.

You assume correctly, but your conclusion surprises me. I think the Combat Knife and the Arc Thrower are the most powerful secondaries in ABB and they would be the LAST ones i'd give up.

Yeah, I always try to bring a mindshielded saboteur on every mission to shut down sectoids. If I were picking classes to swap, it would probably be specialists, scouts, or grenadiers. I might pick infantry if necessary.

Specialists on missions without something to hack, Infantry and Grenadiers would be my first choice if i were to just decide by which secondary weapon is most expendable, it think.
But it also depends on what kind of weapon you want to bring. You can use psi with rifles, snipers, cannons or shotguns now and all of them could be interesting in the right context.

im thinking more towards the end game when youd be ready to make the gear, by then there are so many good skills (and primary weapons) on everyone that those particular secondaries seem to get the least airtime for me.

i tend to build agents more like a secondary scouter. melee is covered well enough by rangers and templars imo.

holotargeting is a rather ubiquitous skill towards the end so the scout feels less needed.

i prolly dont use saboteurs to their best effect.

Good to know on the technical capabilities.

As FowlJ brought up - is it possible to borrow or make Psi Overhaul mod a dependency? I know it's risky, but I think it largely works alongside ABB, and I'm currently running both. It looks reasonably well balanced with training time lengths. More importantly, I can train up long time soldiers without losing what made them interesting in the first place.

I personally feel like losing equipment/abilities to equip a psi amp really hurts what makes characters interesting. The decision will basically become "What class is worst? OK I guess you're a psi op now". More customization options are good, but this lessens customization because it will nullify a large number of abilities.

The goal of the project is to "increase the depth of decision that the player has." I think mandating the replacement of a secondary weapon with a psi amp slightly upticks tactical decisions (who do I make a psi op for this mission) at the cost of a big decrease in strategic decisions (a lot of abilities just became uninteresting because I lose them and no actual commitment to particular characters as a psi op). The other strategic decisions like building armor or particular amps exist either way.

A lot of this boils down to psionics on items vs. people. I think the strategic experience is better placing that onus on people and then using items and mechanic changes (like psi armor and feedback) to balance them. But if ABB soldiers aren't psionically active then of course you use items. But that's putting all of the strategic elements behind spending money instead of developing soldiers. Developing soldiers is IMO a more enjoyable progression element.

I don't like it as much, but if you are sticking with "humans aren't psionically active", I'd personally rather see something like you introduce tier 3 Operative perks that allow the use of specific Amps which contain the abilities. So the player doesn't give up an item slot but it is a valuable perk and there's commitment and pre-planning involved. And since they can only learn how to use specific amps (Oppressor, Dominator, Savior) they don't ever get to the super level of Psi Ops. It also ensures soldiers that make it the longest (and which you're most attached to) get the fun psi abilities.

what if the psi amp was a primary weapon option? even sharpshooters can benefit if they are spec'd as a gunslinger. what would REALLY be cool is if the psi abilities checked will instead of aim. that way with the uneven abilities mod, the psi amp might not always be the best in slot. would make those will implants more interesting too.

Haven't had much enough time to play with this. I do think the core decisions of reusing existing operatives and replacing the secondary are great calls. That makes Psi a new option but not a straight power boost.

But I miss the idea of psi units being special and soldiers having variation. I'd rather have something like Ziodyne's Psi Overhaul or XCOM1 where units have to get tested. And if they pass & get trained, then:
1) They get a unique perk tree that develops alongside as they level, usable *IF* they equip a Psi Amp. As in Psi Overhaul (I'm suspect this is harder to code).
OR
2) They get a single perk like "Oppressor", "Dominator", and "Savior", which determines what abilities they will get using a (generic) Psi Amp. Like a second class each Psi Soldier will randomly belong to. So you build an Amp and can give it to different soldiers to get different effects.

Really anxious about powers that damage the user, but will see how it plays. I suspect I'm just not going to be able to bring myself to use Amps until I get Psi armor or a trait, which feels like a flaw in the system. If technically possible, perhaps the penalty for amateur use should instead be a high cool-down or low # of charges.

I am reasonably confident that i will be able to balance this system in a satisfying way. Making loadout and equipment matter more is a central part of ABB and from the beginning i started moving what used to be soldier perks to the weapons and items. The psi overhaul is just the logical next step and i think it fits well enough into the context of the mod.

I am certain that there are different ways to do things that also have their merit, but this is the one i chose and i am going to stick with it.
Initially, it's likely not going to be compatible with other overhaul mods (like Ziodyne's) because i don't want to compromise on my own ideas for the sake of giving others the options to turn them off. The fact that i am weaving parts of the Psi Overhaul into loottables, tech trees, soldier class properties and other areas means that i won't be able to give you a convenient "ON/OFF" switch either. This is always the drawback with bigger overhaul mods, something that i definetely want to turn ABB into.

As noted further above, i am also neither capable nor willing to make huge technical changes like new skilltree panels, parallel development trees, primary weapon amps or whatever other wild dreams abound. I will have to leave stuff like that to the heavyweights like Maluco or Musashi. Or Ziodyne. I don't really see a reason to compete with his mod.