Hate to break it to you, but according to Wikipedia and IMDb, DiMartino and Konietzko are only credited with the story, with Shyamalan getting sole screenplay credit. And in Hollywood, there's nothing to prevent a screenplay from diverging almost totally from the story outline. MNS is the screenwriter, director, and producer of this film, so it's almost certain to be just as much one of his "auteur" pictures as all his previous efforts. Which means, in all likelihood, it's going to be a pretentious, ponderous, self-congratulatory mess. DiMartino and Konietzko are executive producers, but I wouldn't count on them having enough creative control to cancel out MNS's "vision," given that MNS has far more clout in Hollywood, and has worked with all the other producers on the film before. That means D&K are the outsiders in the group, perhaps only getting a token EP credit because of their ownership of the concept. Even if MNS is consulting with them, involving them in the process, I profoundly doubt they have the power to override his decisions.
These photos are encouraging, there doesn't appear to be any "re-imagining" going on thus far, and it was M. Night taking things in his own direction that was worrying me the most.
I see plenty of re-imagining going on in the casting, and not just where ethnicity is concerned. Shaun Toub as Iroh? Aasif Mandvi as Zhou? Those just seem totally wrong. Toub is too young, too thin, and not jovial enough or commanding enough (from what little I've admittedly seen of him) for Iroh. And casting
The Daily Show's Mandvi as Zhou suggests they may be reinterpreting him as a comic villain (unless Mandvi has considerably more range than I've seen from him in the past -- and can drop his voice by a couple of octaves).