Okay, I kind of decided that a lot of you are either 15 years old, or insane. Monster's Inc Magical Flying Doors is not going to happen - ever. I can guarantee that to you right this very minute. Do I have proof? No. I don't, but I have more than half a brain and every once and a while I decide to use it. Crush's coaster, is a completely different situation at a completely different, not to mention fairly new, park.
I think another thing to think about, is the scene that we are discussing itself. The flying doors in Monster's Inc. These are doors. How many riders are going to be riding each door. Even more importantly, how is imagineering going to plausibly have a flying "door" that seats more than two people. Sounds like it wouldn't be flying doorways anymore. It really just doesn't make any sense at all.
As for comparisons with Stitch??? Come on, the height requirement argument? I worked at the Barnstormer and every third parent would flip out because their shorter than average, or braver than average age kid, wouldn't be able to ride. If they were going to build any Monster's Inc attraction at the parks at this point, it would be a dark ride.
So, it's not going to happen. You guys all get excited about one idea that was not thought out to well and believe it to be true.