I've a few gripes, but I'll narrow them down to two that, while maybe more subjective and nitpicky, would be the easiest to address. Some transformations feel plain and incomplete, and cybernetics are a very understated aspect of the game and could be expanded upon quite heavily.
The raskvel transformation doesn't change the player's face at all despite the rask having bunnylike faces, and the zaika TF lacks arms and legs, and those are just the two I have at the front of my mind. I don't know if there's an internal rule where the player can't have less than five fingers per hand, or multiple arms (even if just cosmetic), but it makes some transformations incomplete.
Cybernetics are such a cool concept, but very little is done with it. You'd expect the ability to get chromed up like the average zaika, or even a full blown cyborg like an XO, but the most you get are implants, one of each, with very few utility options (and most of them don't even have an effect on characters lacking bobs or vagene). Not to mention how late in the game you even obtain them, at the penultimate planet.
I don't like to complain without posing solutions though. For the TFs, a few more effects would be all they need, like the zaika one giving you the appropriate arms and legs. As for cybernetics, I again don't know if there's some internal rules that get in the way of the system or if it's just a case of nobody putting the time into it yet, but I would more than happily write everything necessary for a cybernetics expansion to get it off the ground. Hopefully I could get some information on that.