I'm currently on a build with metathermics as a secondary skill. (ambush energy pistol build with average perception, high dexterity and low will). Note that I did not need to take any feats (at least early on) to use metathermics well. Anything I took was a nice late game bonus but nothing needed to make the use of metathermics viable.
Since I played a lot with Psychokinesis on other hybrid builds, I wanted to try something different and went full metathermics.
I'm surprised how efficient it is, even with 3 will and lower damage.
Cryokinesis is very nice early game to slow down targets and amazing with caltrops. It's nice throughout the game as a long range finisher against wounded targets with its perfect accuracy. Also nice to trigger opportunist.
Pyrokinesis is good to set mines from a safe distance, and combined with pyromaniac feat, has a 50% chance to set targets on fire bringing fear as a CC and light for ambush.
Cryostasis is just amazing on hybrid builds. The high psi cost might be an issue for a full psi build, but as an hybrid build you don't really care to use almost all your psi on an ability. It really shine with its low AP cost, you can use it in the end of your turn to CC anyone even if the target was stunned recently. And compared with TM stasis it is available way earlier and does not prevent you to kill the target with an execute for instance.
TD destabilization is also amazing for any builds that have high damage potential on one target but lack AOE damage (sniper, plasma gun, some crossbow build).
Exothermic aura is also very nice to have. First as a panic flee button. You activate the thing, run to a safe spot and most foes won't follow. Also nice against melee foes especially with low health like spawn. Can also be used against crawler and other naughty stealthy targets. It also makes you immune to heat, can help against few targets or to protect yourself if you need to navigate through fire.
Plus all the other psi abilities that you people already mentioned.
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To sum up, I thought that metathermics was only nice as a damage psi school, this playthrough of the game made me think otherwise, utility is really nice as well and on some hybrid builds it's not weak at all compared to other psi school.