Seems like they want to give leo a personality that isnt just, i am responsible one, but leo had a decent one in the 2014 series of him being a fan boy to that scifi show and what not.
This new dianamic kind of shows all the turtles on equal footing, at least in the previews. Even if raph is the leader, his form of leadership is a huge difference than leo's.
Already you can see Raph as a leader is more unfocused than leo previous incarnations. Which I think is a good thing in this series because, 1 no shredder, and 2 it makes each turtle more independent than the ninja team we are used too.
I dont like Raph being so huge, but that might be the comic's influence when raph was turned into a prehistoric mutant for a while.
Raph to me should be the quick striker type. Not the tank. I would actually like to see a tanky Don type since he he can build himself like that with tech or technique.
Mikey will never change, he cant because the only real contrast to mikey is not donny or raph, but leonardo.
Mikey is the free spirit who goes with the flow of his brothers.