I had no issues with bosses of any kind. I just spam fireball and I always preshield main mage and wait 10 sec before attacking the boss. My Rfc xp was i think around 17k xp per hour (generally level and half).

I am skipping bosses most of times beacuse I am using build only for aoe and aoe only! Once i hit 60 I'll specc arcane fire and roflstomp everything.

So far, lv 38 2 days 13 hours played (5 hours afked) It seems I'll be able to reach lv 43 before 3 days played. I generally wiped 5x across playtime still and I had I think around 23 deaths by solo mages in instances so it's really really good. (at this rate my locks had generally around 100 wipes and around 400 deaths or so and around 6.5 days played).