This has been rumored for awhile and I've been eagerly awaiting an official announcement. I actually hoped it would get a stealth release this year for Blizzcon, but it actually looks like they only just started. While the visual upgrades are apparent, they also look incredibly unfinished. (being generous) I could be less kind, but I think I will wait and see how it looks closer to release. Either way I've been itching to replay these campaigns for awhile now, and the updated interface is all I really need.

I think it's sort of funny they turned Arthas into a Bishounen character. He wasn't that pretty.