I know its a bit suspicious that I'm posting after having so little time, but I'm saying this having mostly cleared the demo.

The 10% of damage that missiles deal as thermal currently seems far more viable then dedicated thermal weapons, as missiles armor shred causes the thermal damage to rapidly ramp up and do more heat against pretty much everything with more then 5 armor in my testing.

Changing the thermal percentage from 10% resistance per armor to 8% armor would allow some (4%) damage to the major medium monsters while still needing weapons with armor shred to go from marginal to effective. (While also making accelerated thermal weapons a very tantalizing counter for say, the rocket hive monsters, which would take 80% more damage from these weapons then they did previously.)

This way stock thermal weapons start functional at the turns you are able to unlock them, rather then being... Oddly out the door/falling out of the weapons roster when they initially appear.

Missiles and fire augments would probably need tweaking to compensate for this (As they are really strong already,) but it would likely do away with a lot of confusion from people who try these things and get confused why no damage is being dealt.