Unfortunately CL builds are very mana hungry. The only way I was able to level up (currently 65 and just switched to arc lash, btw) was using the aspect that gives you mana back if CL hits yourself and the aspect that can proc additional chain lightnings. The first one really only works on single targets so bosses were easy to take down but I had issues with crowds unless I popped unstable currents.

I just hit 65 on WT3 as a Sorc. I actually just recently switched to an arc lash build after stubbornly plowing through on a leveling chain lightning build. For the most part, it's okay albeit a bit boring. I was thinking of switching to rogue as that was my class during the betas but was going to wait until I hit WT4 and see how that power spike is on ancestral gear. I'm clearing close to tier 20 nightmare dungeons (but haven't tried 20 yet) so I may just go for the capstone dungeon.