"Perhaps, I'm disappointed because he promises to explore ambiguity, then gets muddled and gives it a comfortable resolution. For instance, I found the moral ambiguity of "Talk To Her" very badly handled in the last half..."

I, on the other hand, believe that the last half of Talk to Her is quite possibly the finest passage of his career. "Nothing is simple." Almodvar answered the quandary himself. So I'm not sure what made you think that it was a comfortable resolution.

Is he one of the greatest living filmmakers? I'm not sure, but that's quite relative. While I'm glad that you normally don't distinguish between arthouse and mainstream, you are chiding his work because it crosses over. How many filmmakers today could say that about their films? Not many.