That's a truly awful trailer. And you can't really judge a movie by its trailer but the result looks like a bad Lifetime movie.

It feels like the movie is 40% expository phone calls.

So now there is talk that the Magic Eye Theater, which hosted the Big Hero 6 trailer, will now host the Tomorrowland Trailer....in Tomorrowland. Fitting, no?

Very appropriate venue.
How does this "hosting" thing work? Do they just load up the theater to play a trailer?

Basically, yes. It's an extended trailer, usually 15 -20 minutes. But because they use venues like the Magic Eye Theater, Muppet's 3D, and It's Tough To be A Bug, they are usually 3D and utilize the special effects in the theater like lighting, smoke, loud base, or movement. It can result in a better experience than the full movie in the regular theaters. I think movie chains should pay attention! Perhaps DBox (the chairs that moves) is what the start of that.

Been done already (although not real well)

Did that even make it to the theaters? That came out last year and I didn't even hear about it! Sounds like that was a good thing...