I hope it stays 3 hours for a while longer. It's the only way to get more air time for the non-main event portion of the roster. There's no way WWE can rebuild the mid card and tag team divisions as effectively as they have if they have less air time to devote to it.
I don't care about ratings....and in this case, neither should Vince. Without that top tier of talent like they had years ago, they need more air time to give certain wrestlers so that A) they can work on properly building the future of that top tier with what is the mid card today, and B) keep giving the time to today's top tier to keep it alive and moving forward until the next generation of main eventers are ready to step up and carry the WWE.
Without 3 hour RAWs, there'd only be enough time for them to develop and give good storylines to 1 or 2 younger guys at the same time, so most of Sandow, Ryback, Cesaro, Bryan, Miz, Ziggler, Barrett, Kofi, and The Shield would be suffering, and that's not to mention the attention and air time they've given to PTP, 3MB, Rey and Cara, Kidd and Gabriel, etc that wouldn't be available for those teams in the tag division.
It's pretty clear to me that the 3 hour RAWs are needed right now in their attempt at building A) new stars to get to the main event level and stay there, hoping that someone can take a hold of the wrestling world the way Austin and Rock did, and B) building the rest of the card to have legit characters with personality, regardless of whether or not they'll ever get to the main event (like 3MB.....wrestlers and stables and teams like them are needed...they'll never be main event guys, but the WWE always was at it's best when even the lower card guys are given time to develop a character).