Because a hotkey, class based game is automatically a WoW clone. There has never been a good hotkey class based game has there? Well except that one Dragon Age game but shhhhh
Why don't we stop jumping to the "WOW CLONEZ" conclusion until the beta comes out and we actually know enough to judge the game. And to be quite honest, it would be impossible to replicate The Elder Scrolls single player as an MMO. Too many skill combinations to balance and blend, you can't have that absolute freedom to murder anyone you want, a game with well-done, respawning instances > an MMO with a bunch of Skyrim-like, incredibly similar dungeons, etc.
TES:O could have done this. TES:O could have done that. But in the end, until at least the beta comes out we can't call it a WoW clone with any real basis.
Having first-person real-time combat in an MMO wouldn't be impossible. It would be difficult to have with features like 100v100 PvP, however. The question is, what would most players prefer: Elder Scrolls gameplay and mechanics but limited PvP and realm population with more of a diablo-esque public game/co-op feel, with perhaps high population cities; or tab-taget auto-attack with more players per realm?
Also, Dragon Age, whilst not a bad game, is basically ying to the Elder Scrolls yang. If
that's what people want to see, why don't they create a new IP or buy the DA rights from EA/Bioware?