Some characters seem like they don't belong in the OT
 

Some of them look like they are there because of their action figures like Dirtbag, Wingnut, Screwloose, Mona Lisa, Ground Chuck, that fat sumo asian dude with the tattoos, and that red bull guy. I'm guessing playmates told Wolf to put the characters in his cartoon to get kids to buy their figures. Again, I'm just guessing.

I suspected the whole "Planet of the Turtloids" 2 parter was created just to get kids to buy the Ground Chuck, weird sumo dude(forgot name), red bull(forgot name), and Dirtbag figures.

OF COURSE THEY WERE! This was the marketing campaign of the 80's.
Have a new vehicle/character made then introduce it in the comic/ cartoon!
This was the same strategy for Masters of the universe, GIjoe, Transformers, Thundercats, etc.

By the 3rd year Playmates were just churning out utterly rediculous characters/figures. In fact I would say the bulk of the Playmates line had NOTHING to do with the TMNT universe.

They didn't use most of the Playmates mutants though, probably because a lot of them were really stupid looking like Monty Moose or Hot Spot.

Ground chuck and Dirtbag were probably being billed as a cool new mutant pair, they were also in TMNT III for NES. They likely wanted those two to be important.

The Mona-Lisa toy came out later.

I agree that there was a whole slew of really dumb action figures and Turtles in really dumb costumes (like Raph's soccer uniform/ Mikey's sailor outfit)

Some awful wastes of plastic got made. I wish Playmates would launch an IDW line instead of making every mutant character to ever come along on the show!
( personally I liked Rad Brad and Xever more than their mutant counterparts.

The writers probably felt that Ace Duck didn't belong in the show despite his bio card saying he pilots the Turtle Blimp. So he just gets a cameo as a show within the show. They just made it so any Turtle can pilot the Blimp. Usually Leo or Don.

And many characters from.the show were not toys, even though they would have made great toys.

Of course, he shouldn't pilot the Turtle Blimp, since the turtles do it themselves in the show.

If you're interested, I discovered this fanfic years ago. I think it says much how he could have been written.

http://www.fanfiction.net/s/1115105/1/Duck-and-Cover

Ace Duck is a terrible character. He looks like he belongs in Disney as Donald Duck's cousin or something.

Ducktales was airing at the time.

Some of the Red Sky enemies also could qualify, with the H.A.V.O.C. mutants feeling more like X-Men mutants as there was nothing "ninja" about them; Dregg and his enemies feel more like a set of Power Ranger villains; he and Mung treated Shredder/Krang as strangers. That may have been part of the reason why so many tuned out for Red Sky since the casuals felt that by following trends was a plea to get others to join in. Plus, there were no figures of Red Sky characters made also, so that couldn't tell the viewing audience that there were new characters around in the show.

I don't think the Turtles belong in the OT.

I really could not stand Carter! He was as annoying to me as Zach is to most of the fanbase! Hell, I would've prefered it if they had simply brought back Zach as a college student!

I believe her action figure came out in 1992-1993.

Funny you would say that. I remember reading an interview (I think it was with David Wise) who said they were told to introduce a new main villain because Power Rangers was doing it.

Well after 8 seasons of Shredder/Krang, it was probably time to move on.

Oh you.... never change Andrew. Never change.

Actually he reminds me of Launch Pad Mcquack.

Who always crashes...

And some of the 2k3 ones as well. The various random mutants felt like Teen Titans or Ben 10 monsters.