Yes, its fun to rank movies but I don't get the either/or mentalities that some people (apparently from the side that prefers IM) seem to have.
A few reasons why IM doesn't rank on the level of TDK IMO:
1. Lack of directorial "style." It just doesn't have any. The cinematography and shot composition was quite vanilla. No real signature, no distinguishable artistic style. It wasn't *bad*, per se, I just like how movies like Spider-Man, Superman: The Movie, the Burton and Nolan batflicks are all such tangible products of their directors.
2. Lack of a memorable villain. Anytime I have more of a tendency to refer to the villain by the actor's name instead of the character in a genre film then I don't think the villain had the impact he could have. "Remember when Saruman did this or the Joker did that" as opposed to "remember the scene where Jeff Bridges got in that big suit of armor." And often times in movies like these the villain is a more important element than the hero. Look at movies like The Terminator, The Empire Strikes Back, Alien, etc. It isn't the performance of the "hero" in those stories that is typically talked about. A movie doesn't have to have one of the great all-time villains in it to be great (as demonstrated by films like Raiders of the Lost Ark) but the movies that do have a huge advantage.
3. Not good enough action sequences. A movie doesn't have to have tons of action but if it "feels" like it doesn't have the budget the story probably needed then it isn't a good thing. The finale was more "X-Men" than "Transformers" and IM definitely deserves a TF-quality action sequence.
Keep in mind none of the above elements were bad in IM, but they were noticeably lacking when compared to a movie like TDK.
