You had me at cave wizard. Couple questions though. Does 10 con (for thick skull) even make sense if I'm eventually getting LoC? I suppose it would make the journey to that point easier since LoC is level 14 or 16 I believe. Also, should I pick stealth if I'm going PSI? Tranquility vs Psychosis?
If you have a psi build for dominating I'd love to see it.
I don't usually go with high CON for psi builds, just because psi is starved badly for stat points. To make a psi build work on Dominating, you're going to need to have 15 or 16 Will at the top. So then you basically need to figure out if you want to have a larger health pool, or more crafting ability. I take 10 Will, 10 Int (8 Int in the expansion, given what we've seen in the preview videos about there being agility checks in the game world; 5 base Agi is good enough but 3 mostly isn't) because I like crafting. If you don't like crafting, you'd want to consider taking at least enough Con to get Fast Metabolism, which is really great for psi.
14 levels come really quick if you're on Classic XP, and still not too slowly on Oddity. Classic xp, you can be level 13 or 14 when you finish Depot A if you've really gone hunting for the side stuff (you can handle the Burrowers but the Lunatics are sometimes a stretch depending on your support skills). And the side quests for the battery and Hathor are some more easy xp. So don't sweat making it to LoC.
Stealth complements psi wonderfully. Your health pool is lower so you're not really able to tank too many hits, and stealth gives you the ability to position and get the drop on your enemies. But you don't need much stealth, even with the higher detection enemies have on Dominating. 50-70 points with 3 Agi is enough if you can craft your own stealth gear.
Psychosis is objectively stronger at all lower difficulties. Tranquility catches up on Dominating. The reason is that the HP increase on Dominating is such that you're better off not trying to do raw, direct damage to kill an enemy, but rather some form of shenanigans-style damage (like a double TK Punch or Implosion for those pesky Ancient Rathounds, or burning living enemies to death so they run around in panic, or stunning and slowing enemies so you can kite them a bit) and Tranquility lets you use more abilities per turn. I recommend Tranquility for Dominating but Psychosis would be just fine. Would you rather see big numbers (Psychosis) or do more things in a turn(Tranquility)? Up to you.
Sure. Here's the first psi build I beat Dominating with:
http://underrail.info.tm/build/?GQMIAwMDEAoPHgAAAAAAUUYARVVfJTlVS8KHwocvAEAoFys_FCoWLj0hZGdmRlc Idea was to have high initiative because no stealth; high traps because low health; Grenadier because it's an amazing support ability for almost every build; just enough Thought Control for LoC and max out the other two as the bread-and-butter damage dealers. Craft a headband with +crit and psi mufflers, craft a vest with psi beetle carapace, enough bio to make Focus Stims and Trance which help in the bigger fights. Premeditation is a must for any psi build. Force User is great if you think you might like to be able to back up to a wall and hang out, invulnerable, for four turns while your abilities cool down - or lock an enemy in place for four turns. Either way. It's a strong psi build and cruises through the game easily even on Dominating. However, you might consider taking two points out of Dex, putting them into Per, taking those 15 points out of Guns and putting them wherever, and putting Snooping in place of Gunslinger. It's nice to get those extra secrets discovered, and the initiative boost from Paranoia is enough because you'll end up manually starting most fights anyway. If you want stealth, you'll have to decide what to pull points from. Persuasion is min/maxed so that you can pass the hardest check in the base game, but only while wearing the Noble Robe; Hacking makes the highest check; Lockpicking is good enough for all but two boxes (and they don't have special loot, but if you really want is, with Omnitool and +2Dex junkyard surprise you can get those two, also); Throwing is obviously bare minimum for Grenadier. That's the only downside of psi - you're hard pressed for stat and skill points more than many other builds. You want something, you're paying for it by losing something else quite good. (edit: Oh, also, Ballistics ended up being underwhelming so I don't strongly suggest it)
Psi is strong enough that stealth is absolutely optional.
One example I can give is a scenario against Lunatics where if you're immune to stun, you will get Bilocations cast on you immediately instead of Mental Breakdowns. The Mental Breakdown is preferable because it will waste their empower psi skill and there is always another mob after the one that used the Breakdown to put you out of the status. Even though a Psi build has the means to deal with the Bilocation clones, I don't think somebody would want to waste their AP on that, instead of just keep killing Loons.
Yes... there is an immunity for 3 turns, but after that you can still get poisoned and stunned.
Psi is actually extra strong against Lunatics and psi vs Lunatics is one of the places the power of psi is most apparent. If you've got LoC and are fighting a group of Lunatics, you just pull them with a grenade, turtle up behind your Force Field, and when they're all nicely gathered up, you LoC+(something sneaky). You can LoC+Enrage and have them kill each other. LoC+Bilocation if you have a way to trap them in place is decent. LoC+Psicognitive Interruption is just borderline unfair. LoC+Mental breakdown puts them all in incap so you can pick them off one at a time with TK Proxy doubling up your TK Punch or Implosion; find the middle of the group, put a ThermoD on it, and knock it out and it'll AoE two to three times its own health in damage, instakilling everyone around it.
For the most part, you don't hold LoC for the stun resist. You pop it to break stuns (if necessary) and then AoE some monster Thought Control ability.