Many people are going to kvetch about the changes to the specific story. I don't actually care that there are changes per se. What will make or break the deal is the quality of the changes and the strength of the scriptwriting.
Let's face it. Turtle lore is messy, with their origins changing from the original comic to the cartoon to the original movie to the second (or third) cartoon series and getting a full reboot in the current cartoon.
The Turtles themselves went from hardcore homicidal little ninja assassins to goofy, overweight, pizza eating, nobody-ever-gets-killed-or-mained-in-our-cartoon-because-80's cartoons back to semi-hardcore-but-still-funny-but-at-least-we-look-like-the-comics cartoons when they went to the future to the current now-we-actually-look-and-act-like-teens nick show.
April has been everything from a pawnshop owner to a TV News Reporter then back to a pawnshop owner who became a TV News Reporter and then a ninja... and now she's a pre-teen whose father happens to be involved with the Krang. The Krang who started out as good guy aliens stranded on Earth, then became a single, goofy evil brain in a stupid balloon-shaped exo-suit, then went back to being an entire race, only this time they're an evil race.
Then there's the Shredder. Who originally just died. But then didn't. But then died again the movie and came back.
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I think some of the changes will infuriate fans, however well they're made. Making Shredder American, for one, makes little sense. And leads to the uncomfortable possibility that Splinter will also be American. And possibly April's mutated dad (Look in your heart, you know it's true)
And the Turtles are now not pint-sized mutants who are comically puny buy who have been endowed with Ninja skills... but rather genetically-engineered tanks who can crush vehicles with their shells.
That's like, uh, taking an infamously short and short tempered Canadian mutant superhero and recasting him as a six foot tall Australian. While Hugh Jackman pulled it off, somehow, only time will tell if the new Turtles will be able to survive the reboot.
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A lot of us are wondering why they just didn't do a movie version of the current cartoon. But as we've seen with how M.Night butchered Avatar, even with the slavish dedication to the source material, that's not always a guarantee.
