I really don't agree, based on what is in the film. What needed to be cut down was in the writing phase...and truthfully, the story could have removed Catwoman and still had plenty to tell it well with some better elbow room. She was great with what she did, but the rest of the movie could have used the space. But that's just one element.
It needed less stuff...or an even longer extra time than many are suggesting, or two films. And again, that would have been a major slip no Nolan's part. But whichever one thinks...we can't point to IMAX as the reason for it. The responsibility lies squarely on the filmmaker's shoulders. If IMAX did affect it adversely, then it;'s his fault for letting it get to that point.....which may be the case, but because he's still so good at what he does, it still turned out to be pretty good and not a disaster.