I work at a software retail store and I had to pre-order it for the store (working in Media Markt).
The release date so far (came with "all release dates may change") was 28/11/2008 which looks possible to me.
i dont believe thay have offically, because if they did almost all starcraft fanboys would have been going nuts. Now the date does look possible, but i would think WoTlk would come out first?
the date I got when I pre-ordered (had the same on the paper) was 19/9/2008 which doesnt look possible at all with the beta test not even started yet. I'd think first weeks of November at best for WotLK and about the date given for StarCraft II.
makes sense to have both games released around November. I dont think they'd have any problems with it cause they're aiming at different people and even if some do want them both, they're probably going to buy them anyway
As you said, (at least if i understood correct), a game shouldnt grow old while in development. Considering its been developed before its announcement for quite a while now, its already 3-4 years old. Another year wouldnt make it look better, even if the gameplay is as flawless as Starcraft 1 is.
They announced Wotlk for november, So I imagine a month after its release they will really be pushing putting out a new game, after all the WoW lovers come back and buy the new xpac, they can come back and take their money somewhere else.