Downloaded the 1.12 client, and got Elysium server going to try out a few things. Rolled up each of the 4 classes I was considering, and will probably roll up more just try them out.
Priest - Pretty straight forward, but was fun multi-dotting with SW
and then just popping a heal on myself to stay alive and watching them all fall over. This probably won't be very viable or even able to do it on Classic due to massive population. Having heals though was pretty awesome to use as a tool to level faster. Mana management was easy and maybe drank 1 time?
Mage - The most boring of the ones I've tried so far, despite their power later on. No "tricks" to play, just Frostbolt, Fireball, Fireball, drink. Spells hit hard though, and shit dies quick. Just little things, but it was nice starting off with a staff that could melee for 5 damage.
Warlock - Was nice getting Immolate at level 2 to mix things up. Instant cast SW
from Priests is way cooler though. Having the Imp helps out a lot of course, and then getting Corruption is OP. Once Voidwalker kicks in, and you get Drain Life for a little bit of healing, along with healthstones, I think Warlocks just will have so many tools at their disposal it'll be fun.
Hunter - Just like mage, it was nice starting with a 5 damage hitter Axe. Went Tauren, but then read up on things and would go Troll if I was actually going Hunter due to racials. Dead zone sucks ass, and Raptor Strike is super weak. No surprise there. Once you have a pet, and you can just range everything down that's where Hunter obviously shines and is the mega super awesome leveler everyone knows. Of the ones I tried, Hunter was the only one that I felt like it was too early to tell.