You never get tired on taking shots at the FW toon do you, Andrew?
Tbh, Shredder and Krang had a bit of development. Shredder was more seriou and competent in season 1. around season 8 became more serious and competent again and also more threatening. And when he and Krang returned for 3 episodes in season 10 they were working together and not trying to back stab each other. So if you want to count that as character development...
But yeah, we all know that character development wasn't something the FW toon did. Tbh, the 4Kids toon didn't do that much either. The Turtles never seemed to learn the lessons they were taught, and I think Mike and Raph got worse as the show went on. If anything, they regressed.