I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
My complaint would be much the same: the ending was too much the same as the original ending to make this very original. That being said, at least the detours taken to get to that ending were different, and had different outcomes.
Still, the universe was left very much as it was in the original ending, and that left me a bit cold. I want to read alternate universe stuff because it is not only vastly different, but because the different outcomes can expand and explore things that might have been, but weren't.
I didn't get quite enough of that and so while this was a worthwhile read, and I had my hopes, particularly at the beginning, it became clear about halfway through that this would be very similar if not a repeat of the movie.
I know it's stilly to hope that the Teenage Mutant Ninja Turtle one will be better at this point, but I do still hold out hope, as the basis of that Deviation seems like it might allow more of a different outcome.