Maybe the problem with the Tumbler was the same problem with the bat suit?  Maybe in Batman 3 (or 6?), there will be a scene of Bruce asking Lucious if he can have a Tumbler that can withstand missiles and Lucious will say “Yes, I have just the thing, except it will not be able to withstand a kick from a small child or cat claws.”

Secondly, it was known that transporting Harvey would lure out The Joker and it was known (Harvey even alliterated to this knowledge) that Batman would show up to save his ass.  They seemed awfully unprepared when things went ACCORDING TO PLAN.  The Joker shows up and it’s like chaos.  Not to mention the horrible “comic relief” from the 2nd driver of the van.

Now that I think of it, and all of Nolan’s films, he may have a good eye for visual impact or weaving complex stories (I actually do love “The Prestige” and “Batman Begins”), he clearly doesn’t understand humor or timing of humor in a movie.  Poorly timed, poorly executed.