@NAWAF

Very much this.

There is alot going on in the WoW storyline that needs a clean end right now (factions most definitely).

I think Warcraft 4 inbetween WoW and WoW-2 would awesomely take care of the problems present in the storyline that cannot be fixed by just releasing another expansion.

It would also allow for some amazing changes that have kind of been in the cards all along, such as the Forsaken founding their own faction, either under Sylvanas, or under a new leader if Sylvanas is destroyed in WC4 (perhaps her sister, freshly undead, hey, could happen). Or perhaps the Forsaken would just be kicked out of the Horde for all the dag-nasty stuff they've been up to since the end of Wrath.

And hey, maybe the Tauren are now an Alliance race? Maybe due to the way, you know, Garrosh murdered Cairne? The labeling of races of the Horde as "unpure"? Pretty much going against the Tauren beliefs in a way Thrall never did?

Crazy you say, well did you know that originally, Goblins were going to be an Alliance race, but they decided against it due to the Goblins' neutrality, and instead created the Gnomes to take up the mantle of pint-size comic relief for the Alliance? Imagine that, huh.... Alliance Goblins.

And now that the Blood Elves are free of mind control (so to speak) and brain washing, perhaps they may mend ties with the Alliance?

And what about Moira? Where do her loyalties lie? What could she possibly do down the road? She respects control, she prizes power and she's definitely not her father. Perhaps Ironforge would fall to the Horde through the betrayal of Moira?

There's so many things going on right now, and so many different avenues that the WC universe could take, that just can't be done in the time span that the MMO requires to slowly roll forward. And just making WoW 2 would prevent them having to reinvent an existing game world like they did (not too terribly completely) with Vanilla WoW's Azeroth. Everything could be made new, made the way they want it, and it could all be amazing and fresh again, while keeping the familiar feel, style and warmth of the original WoW.

Perhaps Stormwind lies in ruins and the Humans have moved North and rebuilt Stromgarde and taken control again of Hillsbrad? Maybe the elemental devastation has continued with aftershocks and other things and places like Silithus rest at the bottom of the ocean? Maybe the new Forsaken faction's capital is what was once Tyr's Hand, and the Death Knight's floating citadel lies crashed into the side of the mountains there? Even better, what if the new Forsaken faction made its capital in Stratholme??? The Western Plaguelands, now a dense forest growing over the remains of the humans which once filled it, while the Eastern Plaguelands have become a complete hell on earth.

There's just so many possible avenues to explore. So many different paths, and this could be presented very quickly and deftly in the story campaigns of an RTS, versus the slow nature of an MMO.