Got a bit of feedback regarding Psionics and Gazers.
Psi Amp's costs are at fixed 25 tu, both Mind Control and Panic. I assume those are the vanilla costs. However, if I get a high tu (veteran) unit and put them on the Synth Suit (+20 tus), I can get up to 100 tus, which means 4 Mind Controls. On a high strength/skill soldier (over 80 strength, over 50 skill), that means 4 aliens controlled each turn. The 4 psionic soldiers in my ship made every single other soldier completely obsolete, as dogs are better scouts. Not complaining. But that might affect the balance you seek for the mod.
Gazers are, I suppose, a mid game combat race. They got a reasonable armor (can be pierced by focused Gauss fire, though) which makes them challenging, but I find their health pool a tad bit excessive, as they more often than not shrug off High Explosives direct blasts with over half their health. In other words, they are just too tough, even against plasma. So maybe taking out 20 life points or something like that from the base stats would be nice?