krankenstein brought up a short point that I believe is very important for the popularity of Mania:
::The park needs a few more rides like this to make it a full day experience::
This is, in a nutshell, the simple reason above anything else, quality or otherwise, why TSMM will be immensely popular and have a very long queue to boot - DHS is a park that is literally starved for rides. The rides of DHS (not counting Mania) consists of RnR Coaster, ToT, Star Tours, Great Movie Ride, and the Backlot Tour. And of those, two of them (GMR and Backlot) are in essence tram tours with a guide (one inside and one outside that has been increasingly downsized throughout the years), while Star Tours is a motion simulator that is definitely showing its age. DHS is a starving man and TSMM is the giant hamburger he's been craving for years. Frankly, I was never worried how good the ride was because tens of thousands of guests are going to see a ride and exclaim to the heavens, "Finally! Something to actually DO around here!!" I'm not here to hate on DHS, but with rides more and more revolving around movie properties (Disney's, Pixar's, or otherwise), it's not that tough to justify putting a new attraction in DHS. I've always felt the motto of WDI when deciding where to place an attraction in WDW should be, "Don't know where it goes? Put it in the Studios!"
After saying all that, I think TSMM is a good D-ticket that will eat up some crowd. Now the next step is eliminating the tram tour on life support called the Backlot Tour (except for Castatrophe Canyon - just leave it and make it like the old Earthquake ride at Universal, you go in - BANG - you go out.), and drop a few rides in all that wasted space. Then we can get rid of the Indy Stunt Show (also getting a bit long in the tooth) and drop in the Indy ride from Disneyland (or if you're one of those who feel that you can't do that because of Dinosaur), drop in the Indy rollercoaster from Paris. Then you'd start seeing some big time attendance and getting that tween-teen bracket who aren't looking to sit down and watch yet another stage show with a truncated plot.