Depends on whether you consider it to be the same reiteration over and over. I dont, especially since the Portal has only opened twice, and that's probably it. It may open again, as a way for the Burning Legion to reach Azeroth. I find Warcraft to be diverse in story, such as the Night Elf arc, the Undead arc, etc and how they interact. Warcraft's strong story point has always been its characters and their interactions.
Orcs VS Humans: (AKA, Warcraft I)
Orcs show up, start causing trouble, humans react to drive them out.
Warcraft II + II(A), Dark Portal
Orcs show up again, Humans flip out, pledge to drive the hoarde away for good.
Warcraft III, Burning Legion is pissed that the orcs failed TWICE to kick human butt-- and step things up. Use the undead to reopen the portal, corrupt the prince, (blah blah blah)
Suspcision makes Orcs fight Humans again....
See a recurring theme here?
It's kinda like Dragon BallZ--- with new bad guy dejour every season, and every time it is "The end of the world."
Compared to it's predecessor, DragonBall, in which this was not the case.
Warcraft's REAL story, is so overtold and formula based that I can predict the NEXT installment!
Warcraft IV:
Humans, Orcs, Elves team up against burning legion. Burning legion corrupts several key players in these protagonist factions, causing internal strife, Medivh shows up for another cameo, and the Titans get involved.