They've said they don't want to make a normalized raid size, especially mid-expansion, as this absolutely forces everyone to change the way they play the game. You'd force every guild in the world to change their rosters, to either recruit 5 more or drop 10, with a tier about to be released. Because of this, I don't see this 15-man style happening, at least not now, maybe after the final MoP tier is released and has been out for several months, to give time to prepare for the next expansion.
I also don't see shared lockout being removed, as it was stated this being done in Asia does not set a precedent for the US/Europe. We'll see what happens, I still think a 1/2 upgrade wouldn't be a big deal, though it has been denied as the solution by Blizzard. Plus since 5.2 won't feature upgrade-able items until maybe 5.3, the 10m group would be justified in saying they can't attain 25m level gear for an entire patch.
In the end, as a 25m raider, I don't need it to be a gear incentive, but it would be nice to have something to encourage the better players to consider 25m. I'm currently 7/16H in a 25m guild, but I know it would be easy enough to go looking for a 10m and achieve more, simply because it is easier to find 9 other skilled players with compatible schedules than to do the same for 25m. World first is a different crowd so let's not bring this into it.