Please try to give it until the end of the first season. I feel like it develops more as it goes.
Several eps into season 2, and some stuff get better, but it's still not really winning much favor with me. Like, I don't dislike or hate it; but my enjoyment of it is still on the low end of things. More then likely will finish it, but will likely be my least favorite of the animated series. I think my biggest issue overall, is that the turtles seem... semi-competent at best. Much of the first season was them just failing upwards. Almost never winning on their own merits and through sheer dumb luck or pyrrhic victories. That does start to change some as the series goes on, mostly when Splinter finally stops being a lazy asshole and starts taking things seriously himself; but I feel like the 2012 series did the concept better of being inexperienced and improving their skills, while they still seems young and stupid they at least took things more seriously then these four.
And its not like I really got any issue with the revamped personalities, after this many cartoons, comics, and movies; it makes sense to try something that is basically, completely different. The only one that bothered me, was Splinter... until he starts actually being a character in the show and not a gag. Like once he actually becomes part of the story, I actually find I like him a lot, I just we got some of that sooner. I kinda like Smart Jerk Donnie, and Psuedo-Drax Raph. Leo is basically just Ben Schwartz being himself, and does get kinda annoying at times, but if there was more moments like 'Many unhappy returns' where he more or less outmaneuvers Big Momma I think he'd actually be my favorite of the series. Mikey is... interesting being sorta the emotional core of the team, but he feels the most lacking to me, as again we kinda had that with 2012 Mikey, but had the bonus of being something of an idiot savant (for lack of a non-insulting term) where he might not have been the smartest on the team, but had a knack for working on pure instinct. Rise Mikey, just kinda lacks in other departments. he just feels like he's lacking... something even when compared to his others. Maybe just because there's not be many episodes actually about him, it feels like everyone else gets more focus.