Are top-tier skills really worth the points?

[Mad Banana]

Build a hybrid mutant gunslinger, having been playing for couple of weeks and really had a lot of fun (and death...)!
Here are a few things about the skills that I wanna share.
For instance, I would perhaps consider Tinkering I the most useful skill in general, even for melee character who don’t need a lot of ammo, batteries and mod options still worth investing the skill points. However the skill at higher levels (III, or even II) does not seem to be as useful as level I, mostly because I found it far easier to just find a powerful item in a cave rather than getting the recipe from a store (maybe it’s just me though). Even with Psychometry, I can occasionally ‘read’ the recipe from the items directly (as long my skill level allows..) but never find it necessary to build later since I’ve already got one! The only time I found my Tinkering II useful is, when I was asked by a Baetyl to offer a couple of missile launcher, I just constructed them from my scraps and get my reward :)
The point is, apparently there is no need to invest Tinkering II or III in early stage since you cannot get access to the recipe and materials anyway, but even later in the game, you may still find it easier to find the items in a random cave rather than getting a disk from the vendor/merchant, which seems to make the skill tree a bit pointless.
I found similar problems for other two skills too:
Mastery butchering, jerks of different kinds doesn’t seem to be different to the raw meat. I invested the points in particular for the voider gland, however normally I found the corpse just disappear after killing the spider which left me nothing to collect :(
Gunslinger’s skill tree: admittedly, the energy cost reduction by fastest gunner + empty the clip are cool, but does not seem to be worth 400/300 sp. Although it gives an extra few shots per round, but against weak enemies they never would be a concern anyway, and difficult enemies who normally bears with high AV pistols are rarely effective doesn matter how many shots you try..
For the next, I might try a true kin melee build and here is some questions: what is the chance for off-hand attack without spending any points in dual-wielding skills? And if I invest the rejoinder in short blade skill tree and wield a dagger in my off hand (and maybe a long sword on main-hand), each dodge gives me a free attack with the short blade anyway, how does this compared to the dual-wielding skills in practice?

[Kaaven]

Well, the usefulness of some of the skills you mentioned really depends on luck - Masterful Butchery for example, is really useful early on, as you can easily get a Salthopper Mandible, which is equal in stats to the Carbide Longsword. But if you get lucky, and can buy one, it turns useless. Same with Puma Vest, 3 AV with no penalty to DV is great early on... unless you are lucky and find something better.

Same with Tinkering II (cause III is really not that great) - in my current game, I made myself a Force Bracelet really early and it saved my life on more than one occasion. But had I found one elsewhere, it would not be useful at all.

In my opinion, usefulness of both those skills comes down to the fact that despite the great variety of different items in the game, there is surprisingly little choice in high-end gear, meaning that once you have the "optimal" stuff, you don't really need or look for anything else. The butchered stuff is disappointingly mid-level all around and very quickly gets obsolete and, as you said, the artifacts are usually easier to find than to make.

As for the melee character - despite the dev's best efforts, the full-short-blades build it is still the most OP. With exchanging Strength for Dexterity for penetration bonus and the general dominance of dodge over armor it is the best to go with short blades in both hands and have all the skills from that tree. Dual Wielding comes really useful anyway, as it helps you dispatch of the enemies faster, not waiting for their miss or hit... Rejoinder still being useful, don't get me wrong.

[dbennett88]

short blades tree is the nastiest tree in the whole game. rejoinder is brutal.
coupled with the natural DV you develop from agi nothing can even touch you in melee. should you have to run, that same high agi score will help you smoke most enemies from a distance via gun.

[RazzleStorm]

Master harvestry is nice if you find yonder bushes, as then you can harvest an item that will let you teleport even when enemies are near. A nice panic button for when you can sprint away

[Aquillion]

They vary wildly.

Tinkering II is alright (it makes it easier to get some powerful guns, but you can just buy or find them directly.) Tinkering III is nearly useless right now.

Mastery butchery is decent. A lot of the stuff it produces can be sold for money and can be useful equipment. Voider glands are nice, but as you've discovered, voiders can be hard to find.

The gunslinger tree is powerful. What do you mean not worth the XP? What else were you going to spend it on?

The short blades tree is and Rejoinder are brutally powerful. Rejoinder will generally give you more attacks than the dual-wielding skills, but why not take both? Jab stacks with the dual wielding skills, and if you go over 100% chance of an offhand attack, you get extra attacks (so 150% chance means you always get an offhand attack, and have a 50% chance of a second offhand attack.)

However, you may want to invest in DV-raising skills first. DV is vital to short blades builds, since you'll be relying on it for your main defense and need to dodge most attacks for rejoinder to work.