Problem:The only unknown game in development is a next-gen MMO/endthread
what i do know is that blizzard stated just before the release of BC, quite some time ago, that any game following wc3 would exclude events that happend in wow, thus making players go and kill illidan and stuff.. dont know if this is still like it since many things changed regarding wow/wc staff etc...we´ll see ^^
Really I think Blizzard would let WoW fizzle out first, as it will inevitably, and then they'll make a WCIV set a few years after whenever WoW ends. It wouldn't be like them to make a game set so far in the past, because they don't want to tell a story that's already been told. The developers want to create new lore, not make a game based off of things already established. If there's any reinvention of the War of the Ancients then it will be told in the form of a movie, if the Blizzard movies get off the ground. WCIV would probably be the headway into the next-gen mmo, which I can see easily being WOW2. WoW may have one more expansion left it in, whether it open water content or the Emerald Dream, I don't know, but after everyone reaches end game at 90 I think most gamers will be ready to quit and have something else. So I see the next two-three years as the fizzling out of WoW, and WCIV could be on the horizon by 2012. Which I personally look forward to, as a big fan of RTS and the other WC games. I then see WoW reinventing itself for a new generation of gamers, unless a World of Starcraft dominates the scene.
Warcraft: Keeper of TimeYou're a member of the bronze dragonflight fixing time against the infinite dragonflight.Then you don't have to worry as much about continuity, and can even build a new continuity on this part of the lore, which seemed to have dropped off the map.
Personally i think they should remake WC1 with better graphics and gameplay, I never got to play that one, but it sounds quite interesting.Second choice go ages back in time like The Sundering or The war Of The Ancients.
You should take into consideration that time travel is now possible in WoW thanks to the Bronze Dragonflight (of course due to infernal meddlings of the Infinite Dragonflight...). That in means in a split-second (Faster than you can say "Flame Wreath! Nobody moves! Oh shi-... ) we can have an all-out war that can last a millenia and in no way it would affect the ongoing WoW experience...Its cheesy but possible(Edit : wrote this before I read what GenXCub said...he beat me to it :) )
I know mmo's that that have been for over 10 years, that aren't anywhere near as popular as WoW, and they are still updating, and being successful and stuff.WoW could still last for a long while, but it is most likely that it will be looking very different from the WoW we know now.