I was looking at the newly released Diablo timeline that is part of the 15th anniversary and I saw some things that lead me to believe that D3 should be here for March. I'd take this with a grain of salt though.
Looking at D2, the beta started March 30th, 2000 and the game was released June 28th of the same year. That's not exactly what I'm looking at... since it's already been three months since the D3 beta started. What I'm looking at is the fact that they included the announcement of the intro cinematic for D2 (same day as when the beta started).
So... taking this and looking at when the D3 intro video was premiered (December 10th, 2011) we can assume that we could possibly be getting D3 around March 10th.
Thoughts? Yeah, anythings possible at this point... but it just seems weird to include the intro cinematic announcement, unless they just needed something else to fit on the timeline to make it look more filled up.