I've been using the mod for at least a couple of releases now (I think I first subbed back in A17), and I love it. You're one of the only mod creators who's made an effort to balance their content, and I think the more recent additions (the rings, specifically) are an excellent addition for that purpose. There's a few tweaks and ideas I'd like to float that I think would further improve the mod:

- A right click toggle for auto-levelling a desired skill when the mage/fighter levels up. I'm primarily thinking of the 50-point sink, which presumably usually gets done once everything else has been levelled. But an option to set your desired skill to level also be useful in early game to cut down on micromanagement a bit.

- A gather point for mentoring magic and skills. Often I find that the autocast for this doesn't find a target; a dedicated work order/restrict type/gather spot might help to ensure regular mentoring takes place if the player's got it set to cast automatically.

- Enchanted furniture. Things like dream/memory transfer (passive mentoring) or mana regeneration via beds, walls that slow hostile pawns within a certain radius, materials that self-repair when magic-bearing entities are near... lots of possibilities here. Magic-based recreation/artistic stuff would be interesting too.

- Blood mage. A mage class that doesn't use mana, but draws their casting energy from freshly killed corpses. Spells would focus on the manipulation of blood - in and out of the body - and could include passives similar to the psionic. Blood magi could boil the blood within an individual to damage or down them, or chill the blood of pawns in an area to slow them and impact their manipulation. The ultimate could be a fast-acting induced hemorrhage that causes targets affected by it to bleed from the face and orifices, giving negative mood debuffs to surrounding pawns and weakening the afflicted with blood loss.

- Magical beasts. Common and uncommon alike would hold a lot of interesting potential. You could have wandering minibosses with similar rarity to thrumbos and strong passive/active magic (or fighting) abilities, along with more common beasts for hazards or quality of life improvements. Small animals that leech mana when they attack could be bred and trained for combat. Lumbering monstrosities that create localised elemental hazards could serve as killbox counters. Lightning minibosses could disable nearby electronics; fire could simply start fires around or behind itself as it moves, and stack burns on pawns within a certain radius of it. Ice could freeze the ground it walks on, or bring snow while on the map. An undead miniboss could resurrect corpses it approaches, turning graveyards into potentially deadly leverage.

You could also go for full-blown boss encounters if you choose to take this route, as a lategame challenge for colonies with developed casters/fighters.

- Wandering Necromancer/s. Event in which one or more necromancers enter the map to raise corpses. This could either be a neutral event, or a raid, with multiple necromancers entering the map with a large undead army.

- Mana crystals. A potential fuel source/consumable that could be added to random generation as an uncommon/rare ore type, for the creation of mana potions or advanced magical technology.

This is what I've got off the top of my head, hopefully some of it strikes your fancy.