there's no way it will 'kill' WoW (the WoW dev team are doing that by themselves.. ba-zing!)
there are many of us old school blizz fans who prefer starcraft over warcraft. and in general i prefer sci-fi over fantasy/medieval stuff. and i know alot of us are craving a decent sci-life mmo to play (which i think our only hope at the moment is tabula rasa?).
at the end of the day tho. the fact is, it will be good. and i will be there playing it. and last but not least, there is no point getting excited as it IS blizzard and anyone who has followed them knows they have a habit of taking their sweet arse time.