Only a lull if you're doing Mythic BRF now, shirley?
But yea, once 6.2 hits, and we get Mythic Dungeons and Tanaaris open, as well as timewalking back to WoTLK...
I resubbed, with the wife, in December, having not played since just after TBC hit, and wow, a lot changed (odd that)
So depends how long since you last played as to how much has changed, but there's still a lot of content to go through just in Draenor, let alone any expansions you may have missed. Leveling is fast now too, so not difficult to cap out at 100, and then explore/raid/whatever