I hate to say it, but part of me is kind of feeling this vibe too. First Splinter, then The Foot, now Shredder (although I can totally see how it can work for Splinter since pretty much only two Asian actors have ever portrayed him - and that's only voice acting). It's a silly comparison but it actually kind of reminds me of the character of Feng in Balls of Thunder, in which Christopher Walken played an "Asian" villain. Obviously it was the film's big joke, but it does seem a bit silly to give the Shredder that same kind of treatment. Yes, he IS Oroku Saki; there's no way around that.
Then again, I'd totally rather have a white American actor play the Shredder than go the Colonel Shraeder route. Bleh. 
I too want to give this film the benefit of the doubt. Despite all the negativity surrounding this movie, it still has peaked my curiosity.
Now, if the teaser looks god awful, then yeah, I probably won't bother. But I'll be patient 'till then.