I'd turn my first character, a Trill (non-joined) into either a Joined Trill or aliengen. Probably the latter, for the sake of variety.

I don't think I would species-change any of my other characters, but I definitely want to re-trait some of them.

Dunno about re-species, but I'd like to re-career my fed engy to a tac.

I'd Change my first toon made the day game went live (tactical, btw) from betazoid to caitian. maybe switch one of my Klingons to ferasan.

I would possibly change my Human Female to a Joined Trill Female. Not sure on that one though. Mostly I want to change her traits around.

One thing I forgot to mention that I guess is near indifferent now;

Creating a midget makes it a lot easier sitting on the pipes versus rebecca.
It can be done with a tall character but the taller you are the closer you have to move to the plasma.
In addition you will be able to take cover where others can't.

I would turn my Betazoid science captain into a Vulcan.

Why? Because vulcans are very iconic to Star Trek, and yet none of my Boffs dialogue-wise make for a good vulcan. Therefore, I'm the best for the job when it comes to representing them.

Plus, there's oodles of vulcan things in this game to take advantage of and feel more connected to.

male trill to a male joined trill

also would like to make him a tac but that is not that important

Same, I would like to be able to switch my caitian tactical captain to science. As for species, I'd love to switch her to Liberated Borg Caitian if Liberated Borg wasn't a human/klingon only option.

Human to Alien. For the customization.

I'd just like to re-trait Weyland since when I created him waaay back, I had no real clue what the traits do...