The funny part is, it looks like due to the way Fremantle dialogs misuse screen estate, there is never a reason to use them for anything serious. Wondering if this should be filed as a bug for Fremantle...
For the dialog layouts, the idea there was to get more vertical space for dialogs, while at the same time doing a change that could be done for the Fremantle scope and timeframe. Yes, horizontal space is therefore reduced, but since we're pretty much getting rid of all the split screen UI designs anyway, vertical space is more useful than horizontal space.