I am pretty sure they are staying with the same time line that they had with the Evo. I wouldn't call what Sprint is doing unexpected PR moves, after all, they have more platforms to support now that WP7 is in the game, and also, there are a lot more android devices out there, so, seeing that they didn't have much to show in time for CES, they tried to get the Evo 3d out in a hurry for that February event before MWC (which most American carriers don't give a dogs rear end about, it's more for us to see what the handset manufacturers are up to) but when the Evo 3d wasn't ready yet, they pulled the Echo out of the hat. The Palm Pre came out at CES and took forever to get ready, that wasn't really a Sprint event, that was a Palm event with them trying to save their butt, Sprint just happened to be the partner.
So, more platforms, more Android forms do equal more announcements. I think they are right on track.