So what classes do you all prefer to play for arena? For me, it's Shaman, not even close. All the removal's insane, and Fire Elemental is just bonkers.
If you're trying to maximize earnings, Paladin, Mage, and Warrior are the top three classes, and there's a big gap before any of the classes inferior to the big 3.
Fire elemental is nuts, but relying on Rare board clear is really crippling for shaman. You quite often get no lightning storms, and that can easily leave you with an unwinnable game before Victory Elemental can come down. When you get the lightning storms, shaman is pretty powerful, I got a twelve win run one out of the three times I tried shaman after they added 12 win runs and the Mind Control nerf.
Paladin, Mage, and Warrior are probably close enough that whichever of the three you have a knack for would be a good place to start practicing. I think Paladin has the best 12 win potential because Truesilver is more stackable than Fiery War Axe. And I would say Mage is probably the hardest one to get stuck with a really unwinnable draft: as Warrior sometimes you get offered very few weapons and you can't generate card/board advantage, so you get empty hand syndrome. Mage always has card/board advantage available, even in a 30 Wisp deck.
I would seriousface recommend against allocating lots of arena practice to a class that's not in the Big 3. Doing better with the other classes is probably a symptom of higher variance making 7 win runs easier with a beginner skillset, or just sample size or an overall general approach that works for that class. Before the mind control nerf there would be swarms of Priests in the 1-3 win range that only knew how to win if they were able to draft mind controls, and they would never make it to the 7-9 win range, which is mostly populated with big 3 classes. I suspect they stunted their own growth that way.
The funnest way to play arena might be in the other six, but building up a card collection can be so critical for enjoying Play Mode. Save the bottom six for after you've mastered the top 3 so well that you have 1000 gold and most cards unlocked.
I have most of the cards, but there are still some I want.. kinda. I have most of what I need. When I'm in the mood to get some cards, I play the big 3, preferring Pally the most out of the big 3, that's my favorite. When I have so much gold I want to lose some I like to play Warlock.