Sorry, I'm a numbskull, and can't lift the image from google maps to edit it.
I agree with Regent Street having great potential, especially to connect Gallivan Plaza and City Creek Center, but I'm completely unconvinced it would work well for people living there. IMO, it has one of the worst views in the city.
That is one hulking, ugly, oppressive, unfriendly garage. I wouldn't want to live across from it.
I think there are a couple other flaws in the proposal as presented, though I did notice that most of the MUAH building was saved. I like the white building, but I can't imagine using an esoteric, 1960-'s, mid-rise office building for the lobby of the theater, no matter how much I personally like it. I also don't really know what the rear of the Tribune building is like; I assume it was built with the tower, though I'm sure there isn't much of anything interesting there--the entire property would be a great adaptive re-use. I think the theater proposal could happen in this area with a bit less demolition, and more creative use of the areas that are available.
Something like this (please excuse the clumsy rendering):
Grand Foyer, Main Street through to Regent Street. New pedestrian access to Regent street along 'Orpheum Alley'. Black box theater to the north on Regent St., Broadway Theater to the south. Mixed-use renovation of the Tribune building.