akjone02: After some more time with the game, more specific suggestions, some reiterations.
Humans need either a small bonus to research or BC production, or should get a solid bonus on trade treaty and research treaty returns. This would help simulate the passive BC and research bonuses they had in Moo1 and Moo2.
Psilion should regain their "creative" trait which gives them all technologies at any branch that requires a choice. I think plenty of techs already give you the choice mechanic, but maybe a few more could be added.
Mrrshan should get a bonus to beam weapon accuracy and possibly damage (including PD weapons of course).
Bulrathi need a bonus to ground troops unless high gravity does that already. Would also love to see them get a small bonus to ship hitpoints.
I disagree with the idea of adding governments, I don't think its necessary to vary the races. A couple small tweaks and we're already there I think.
Disagree about governments. Was always crucial not just for default races, but for customized race design.
That said, if you implement more selective techs (and you should) then I agree Psilons need to be creative, again.
Humans need help without charismatic and leaders. In MOO2, Humans were quite weak, but an early good leader (which they would got reasonably often) could transform their early game. Honestly, I'd bring leaders back and give Humans charismatic.