Indeed,

I leveled a 4x lock/dsic and then swapped to mages later on (4x mage/disc).

The reason I swappepd was mainly group pvp, but locks are insanely fun as well. Main problem with wpvp with locks, 1 good mage will cause slight trouble,group of 3 people can wipe you.

On the mage side, I was able to solo 10 people with 4x mage disc. But if you ignore pvp side, locks are incredibly op once they hit bwl part of gear.