Ion Hazzikostas said there would be more beyond 6.2 in the form of story continuation. Whether that means 6.3 with a lore + questing patch, or 7.0 with a moving back to Azeroth (or to OgreLandDraenor) or it means there's a 6.3 mini-patch and a 6.4 major patch, we don't know.
First they said there would only be two tiers, so 6.2 was originally the last patch, now they're saying they have more story to tell. So, I don't even think Blizzard knows what they're planning anymore.
The whole Expansion should have ended with the destruction of the Dark Portal. I mean leave the damn Orcs where they belong on Draenor another planet and lets just keep an eye on the location of the Portal and if shit starts coming through have Jaina blow the shit outta them with the Focusing Iris.