The guys who made WC1 and 2 and 3 and maybe even WoW 1. Aside from Metzen and everyone who is left who was there at the start.
Over the years Blizzard had quite a few splits, one of which created ArenaNet and GW1/2 (this was during BC development, when there were apparently huge, huge fights for the direction of the game), another with Hellgate London crew, another where a bunch of people went to Red5 and make Firefall, so I guess it's safe to assume quite a few of the original peeps who were there for the WC games are gone now.
Would they be happy to see what Warcraft has become? Or would they weep silent tears of rage and frustration?