MDA will only fail if it's approached from a "the model must be complete" perspective. MDA isn't really a process and IMHO fits nicely with Agile processes.
I disagree, even just coming from the perspective of agile practices (rather than agile ideals). I don't see how you would easily engage in test first development. Infact testing in general is a challenge. Same goes for refactoring, you can adjust the model, but what if you're trying to overcome other challenges, such as streamline to make your code more performant. MDA hides all of that away. It is true though that the more people centric agile practices are still valid (retros, stand ups etc.), but these would be valid in any situation.