If I could reroll to same iLvl Lock from my Hunter, I'd do it. Hunter specs are the same rotation wise, no flavour.
As a Lock you have 3 clear options: DoT spec, Whack-a-mole spec, Nuke spec focusing on massive hits with Chaos Bolt.
For the expansion after WoD, I sincerely hope they revisit all classes/specs(especially the pure DPS classes) and remake them from scratch like Warlocks.