I stand well and truly corrected about the state of the Utah Theater. While some damage has occured over time, it is actually in pretty good repair. I'd love to see it reopened in some capacity, while also building a new, modern theater for broadway shows. I like some of the locations mentioned along West Temple, especially the parking lot to the south of the Peery Hotel; on 300 South as a site. I'm glad there's a concerted effort that's started to save the Utah Theater. My opinion on it just swung 180 degrees, just by seeing some interior pictures.
I've always hoped for a convention center hotel to replace the Shilo Inn. I utterly loathe that building. It is god-awful. Probably the ugliest building in the city right now, IMO, and not because it isn't maintained. To think it replaced a building that was designed by Louis Sullivan!! Granted, it wasn't the best building Sullivan ever did, but it was designed by the father of the American Skyscraper, and was definitely a great example of his style. It was certainly better looking than the F-ing Shilo Inn.
I think the site of the Shilo would be plenty of room for a 1000+ room hotel--It doesn't give anyone much room, except to build UP. And it it directly across the street from the Salt Palace.
Other sites that I think a convention hotel could be built include the corner of the street opposite the Shilo (the NE Corner of 200 S. and West Temple), the site of the ExpoMart (200 S and 200 W, though that does face the loading docks of the Salt Palace). Or the site surrounding the old Zions Bank building (the SW corner of 100 S. and Main). I don't think that such a hotel would go to the north, as all that property is owned by the church, which would be very hesitant to give any of it up, or allow alcohol to be served on it in hotel restaurants and clubs.