Just so we're clear here...Michael Bay did not officially say that Megan Fox was playing the role of April O'Neil in NINJA TURTLES. He said this:

"TMNT: we are bringing Megan Fox back into the family!"

But as you all may point out-- what other role would she fill? Karai???

Regardless, when a fan asked TMNT co-creator, Peter Laird about his thoughts on the topic, this is what he had to say:

My only exposure to Megan Fox as an actress is through her role in two "Transformers" movies and the wretched (but happily forgettable) "Jennifer's Body". It may not be fair to judge her range of acting skills just from those three movies, but I think it is safe to say that there are probably hundreds of better choices for the role of April O'Neil. Of course, her name has promotional value, and maybe that's what they want. Who knows? I can't get myself too worked up about it.

I agree with this man. Definitely nothing to get worked up over. While, I may not agree if that is the casting choice for that role, it's still going to happen. Maybe she won't be so bad.

My favorite April O'Neil? Judith Hoag.