Humans who actually like being mutants in the franchise?
 

Most of the the time when a human becomes a mutant they consider themselves a hideous freak and an outcast from society. There are a few humans who liked becoming mutants however:

1. Bebop and Rocksteady. They liked being mutants so much that in one episode they worried that Krang undid their mutations when he used a holographic projector on them to make them look human again. Either that or they were so stupid that they didn't care what they looked like. But they never showed any desire to become human again.

2. Mutanimals. Man Ray and Mondo Gecko who were both human in Archie and seemed to like being mutants.

3. Perhaps Dogpound? He really shows no regret about not being human anymore.

I think Splinter from the 80's toon liked it after Splinter No More and realized he needed to be a rat or else Shredder would have won.

Plus Pulverizer from the 2012 show wanted to be a mutant really badly so I would think he'd end up liking it eventually.

I don't know if this counts, but in "The Gang's All Here", Michelangelo was thrilled to be a Turtle after he was human, even though Michelangelo was never human to begin with. I can see why though some would enjoy being mutants over humans; they feel more unique and enjoy the abilities that being a mutant provides.

If I remember correctly, Muckman & Joe Eyeball enjoyed being mutants at the end of the episode featuring them, as it turned out to be more exciting than being simple dustmen.

Super Shredder

Perri the "Flying" Squirrel from:
http://tmntentity.blogspot.com/2012/...pecial-11.html

Does Mona Lisa count? she certainly didn't seem to mind it too much, and it got her close to Raph, so....

I guess it depends if Don gives him arms and legs and he gets awesome powers. Otherwise it will really suck to be a bunch of self aware organs floating in a jar. The old toon made little sense thought how can you shapeshifter if you're basically organs floating in a jar with robot arms and legs attached to it. How the hell does that work?

Archie Leatherhead.

It's good to see he grew to accept and embrace his transformation, as he wasn't very happy about it at first.