Duo Leveling Class Comps

[Mercbeast]

Warrior + healer (paladin or shaman) would be my choice.

Warriors are unstoppable with a healer supporting them. If you get ganked, paladins and shamans are both very tanky and freedom/dispels from paladins ruin anybody trying to kite your warrior. It's also generally fast to pug a few DPS when you want to do dungeon quests.

At launch me and a buddy did Shaman/Warrior. Keep in mind that I was the 2nd shaman to hit the cap world wide, and he was like the third or fourth warrior world wide to cap.

It was a terrible combination. Neither of us had great DPS, anything that involved a lot of killing was quite slow. For classic I would not recommend a warrior + healer duo unless you're dedicating yourself to a lot of instancing and picking up DPS to pug.

Duo picks I'd put as top tier, would be, any combination of, Hunter, Shadow Priest, Warlock, Mage, and maybe rogue (rogues start off slow, and then become absurdly fast as they start to round out their abilities and talent points in an ambush build). To be fair, I never played my shaman as elemental, I was using a 2h'r and windfury to help my warrior bro get the most out of his abilities, and elemental shamans were objectively better DPS back then.

Duo shadowpriests can do things like, just run dotting everything and psychic screaming whenever the mobs pile up too much. Can do what are essentially enormous AOE pulls like this, even though you're not really using any AOE abilities.

(edit) Disregard what I said about warriors, I was under the assumption classic was going to be an early version of vanilla, not august 2006. I have no clue about the state of warriors in that patch, though my suspicion is that they are strong.