I don't get why some people say ''spoiling the next expansion'' you wut m8, there's no direct referance saying the next expansion is a 40 year timeskip. They could be forshadowing an eventual timeskip through several expansions, hell it could even be in a Warcraft 4. This is the type of major thing that could indeed end in it's roots, an RTS. (Not that it would really matter to me one way or another)
The ''spoiling the next expansion'' thing is nonesense. Expect several expansions before that, expect more ''Mists of Pandaria'', aka more personal conflicts. Warcraft is nowhere near over, however, they are pointing at what the eventual end will be.
Oh and fun fact, the entire Comic is a flashback from the very first panel, see the white hair on the eyebrows?
As a side note, maybe people can stop bitching about Illidan, as Illidan is obviously the one who will deal a major blow to the Legion (like he should be), and not ''the chosen one'' like some of you people have been moaning recently.