Hammer Wizard works because its max strength has a twofold use - Balor's and Corporeal Projection. When you use any other psi school that isn't PK, strength drops in usefulness and it's harder to justify max strength when you could get more mobility or better psi. Hammer also works best as a tank build because Fancy Footwork has minimal utility with only 3 strikes at most on a 50 AP turn, and Hit and Run is affected by Armor Penalty. You're reduced to only a couple of choices for MP: Sprint, Super Steel armor (which makes you more vulnerable to melee compared to Tungsten), Jumping Beans, Contraction, and Escape Artist which needs too much investment for little reward (7 Dex AND specialization points to get MP, not to mention it's on a cooldown and is entirely conditional unlike Sprint). Even if you were to go for SS armor and minmaxed everything, you'd barely scratch the low end of 100 MP for a couple turns, and you'd be giving up a few key things that hammer builds like to go for. Really, just lower Strength a little bit for Wil, stick to a tungsten or TiChrome hammer, and only use Balor's when buffed with Vitality Powder (situational but still useful).
Dexterity should be 3 for hammers unless you're building for crits, but that requires a *very* specific build which leaves your melee capabilities lacking compared to a hammer wizard. Tanks just don't really get much use out of initiative - you're not an alpha striker. Quick Pockets is simply SHIT and should not be taken on most builds. Grenadier makes it so you rely too heavily on grenades instead of using your build to damage shit. Trigger Happy should only be taken if you're challenging yourself with Ironman, otherwise savescumming will do if you really need to go first, and you don't because you're a tank. Staying with the initiative feats, Paranoia is overrated because of the wide availability of Detection boosting buffs and equipment and its only upside is not having any requirements to get 5 extra initiative; and let me tell you, 5 points won't make that much difference by themselves.
Even if you're to go for Super Steel armor, I would still recommend Sprint. It helps so much as a gap closer. The only time I would not get Sprint on a tank is if my stat spread simply does not allow me to get 6 Agi without sacrificing other feats that I consider more important.
9 Con is mandatory, full stop. 10 Con for Thick Skull is optional, I don't consider it as good on a tank as on a dodge evasion build, but even there, Bullheads will cover you for the harder fights. Last Stand just gives you much needed tanking ability that will let you survive those extra turns needed to end a fight. Juggernaut, Conditioning, Stoicism, all these require decent to high Con already. And let's not forget Fast Metabolism, which makes Regeneration Vests go from amazing to god tier, and helps with psi boosters on top of that. Mechanical damage is the most common in this game by far, and anything else is far behind enough that you can prepare for it and switch out for the appropriate equipment.
You DEFINITELY want 7 Wil for Stoicism. Even hammer berserkers get it, it's not to be underestimated. It will also help with damage for MT, which even if you got mostly for Pyromaniac and the non-scaling spells, you will still find yourself using it often for ranged damage. There's no workaround, all builds want a ranged option. And as a certain boar has said, 3 Dex Throwing is still useful, mainly because hammer as a weapon is very low on feat and skill point requirements so they can get a lot of shit as they want. Higher Wil will make your MT stronger, but it will also take away from your other stats which will see higher use.
6 Int is of course needed on a SS tank. It might still be good on a tungsten tank due to Premeditation, but otherwise, 5 Int is the minimum: you absolutely want Expose Weakness.
If you want to wear the Praetorian Lawgiver, it's best on a tungsten tank. It will hamper your mobility too much on a SS tank. Besides, Yell is already good enough with its specialization bringing it to 50% of Intimidation score. Besides, your helmet slot will be better spent on a psi headband.
I'll give you the 101 on Metathermics. Cold spells: SHIT. Thermodinamicity will not justify itself unless you're focusing on psi, in which case just play a pure psi build.
Cryostasis affects ONE target for TWO turns unless you get Cryogenic Induction, but what the hell are you doing specializing in single target CC/damage when Underrail has 6+ enemy NPCs on average every fight? And add a high psi point cost and cooldown on top of that, it's awful. I have never used this spell.
Cryokinesis is "decent" if you're a Psychosis pure psion, but you're not.
Cryo Orb is the only good cold spell, and guess what: it needs Psionic Mania or it just won't be worth a slot compared to a fire spell.
Cryogenic Barrier - I don't think I need to explain why it sucks.
Cryo Shield - why are you relying on a 50% chance to protect you from only MELEE damage when you're a tank?
Now take a look at fire spells.
Pyrokinesis isn't very good for damage unless you're a crit build, but with Pyromaniac, it still kinda works as an AoE fear. I say kinda because it's still only a 50% chance. Good with Premeditation though.
Pyrokinetic Stream is the outlier in fire, being not very good and needing you to specialize in it for it to be any good. It's still an okay last ditch attempt at fear early game if you've got Pyromaniac.
Exothermic Aura is great, giving you fire immunity and screwing with meele NPC AI. And it's budget Escape Artist with its ability to burn a net.
Thermodynamic Destabilization is fucking amazing; when applied from full HP, it will severely injure if not outright kill other NPCs when it goes off. And if you're a tungsten tank, you will resist most of its damage, giving you no reason not to close in for the kill. SS tanks can also resist most of it but only late game. This is the one spell that you want to max Metathermics for if you're still doubting.
Plasma Beam was a great addition to MT, giving you energy damage to deal with those pesky bots. Unfortunately, it won't see much use on a hammer build outside of hoards of bots where you want AoE damage, or Fetid Marsh. It's still a better use of a slot than Cryokinesis or Pyro Stream.
