Well, to be perfectly fair, one could see what angle he's coming from, if you mean Melee as the base game, and UMS as a separate entity. Diablo has since been overrun with bots and hackers, and very few people play WC and WCII anymore. Not to say no one plays, but it's a small margin.
WCIII's community is very much largely composed of DotA players, which is more or less only using the WCIII base engine and level design as the basis of the game. Otherwise, it is the most heavily played map in UMS, and there's at least 75% of the gaming list being filled with DotA games. I'm not sure if that's changed on Europe or West, but it is certainly true on East, and fro what I have heard, Europe has a higher quality of DotA loyalty. Additionally, various and numerous mods have been released for Starcraft and Diablo II. SC's LotRishes maps were going very strong from 2001 until about 2005 or 2006, with a new map every few weeks or so; not to mention there's been a serious number of mods, and the mapping community I was once a part of is still going strong. DII has Dark Alliance (in a Beta, one Act version that has been in development for over five years), Median, and others, which are actual mods.
SC: Ghost was dead before it hit the ground.
@Mulley, I believe they are going for random levels + certain static levels, like they did for DII (eg, Durance 2, random, and Durance 3, static). As it turns out Blizzard is too afraid to do anything truly revolutionary, but then again, if one thinks about it, it's never been their style.