Bellagio can't really change, the joint doesn't get much play on their slots anyways so it makes little sense to turn it into a slot lounge, or for the really sick out there, a keno lounge like the Mirage did to the poker room. Only thing books do make money out of is expanding the race side as they make very good money off of race bets, especially since they are forbidden on giving cash refunds on action as they were starting to do in the early 90s. One thing I think books could do to make more money is strategically place a window or two with a small board in the casino area. They will get more impulsive action from their good customers, the ones that don't spend their whole days in the book, but actually spend it on the floor.
As for best book, I think best place to bet on the Strip is the Barbary as you get the Coast lines which are generally the best in Vegas I would say. Stardust runs second. Best to watch is probably Mandalay or NY NY with the ESPN next door to the book. None is really a good option for football season though, the capacity of the books is so small. Imperial runs a showroom that is converted to an NFL watching room on Sundays, that is a good option guarantees getting a seat and a view of all the games. Boardwalk has a little alcove which is small, but usually not that crowded to watch the games. In general best place to watch games is off the Strip in a sports bar somewhere...