I bet the only reason they put the all caps in menus is so people would have something obvious to complain about that overshadows any other complaints they might otherwise have, and which they can trivially revert for RTM. I've heard of this technique used by designers to manage their bosses/clients' need to feel like they're putting their stamp on the project, they will deliberately put something obvious in that they know their boss won't like so that when he comes over to do his obligatory bikeshedding it won't be anything else the designer cares about.

Personally I thought the way caps were used in beta worked just fine, whereas I don't like them in the menu bar at all, go figure. Maybe they're trying to be semi-consistent with Office 15?