Oh god…my worst nightmare. I guess priest. I love all three specs a bunch, and if I feel like dps I can go shadow and if I wanna heal, I can go disc or holy. So wouldn’t get bored too fast
But lock would be a close second. I just couldn’t give up healing. It’s def my favorite thing to do
If I had to pick one then it would be my druid so that I can swap to any role
My mage… polymorph… make my own food and drink port everywhere for free to any major city…etc…
DK for sure. Being able to basically solo all questing content and compensate for bad healing and bad dps as Blood gives me great comfort. Then when I meet reliable heals and tanks, I can happily switch to frost for more fun.
Warrior. It’s what I’ve played for years now through good and bad.
One class? Just one… um… uh… uh… panics in Altoholic…
DK
Its literally all I play since wrath, one character
Most likely hunter. I like having the option of ranged or melee dps. Doesn’t hurt that it’s pretty easy to play too. Only thing i would miss would be the plate mogs.
Death Knight always and forever, they grabbed me by the throat when I played Wrath when they came out and never let go. The lore, aesthetic, sounds, all of it just makes me happy.
Hunter, but given my luck in life, we’d quickly go back to needing to carry around ammo and having a minimum ranged distance.
deathknight
Druid for sure.
Not because of the 4 specs, but because they can do just about anything regardless of which spec you play… That and I’ve been playing them for ages, so I can play it instinctively.
Best all-rounder class by far, and I absolutely love the lore behind them.
Druid, I get to shoot stars and call down lasers on people.
warlock for sure
Hard choice.
Hmm.
I guess it’s a toss up between Shaman and Warlock.
I’ve played Mage, Pally and Shaman for so long but I think I would have to say Shaman. Ele is by far my favorite spec and I believe the healing spell animations are the best out of any healer. Not being able to tank when I’m feelin it would be a bummer though.
Mage, easy. Decent versatility without any possibility of ever being asked to tank or heal, teleports, no need to buy food or water, cool fantasy, and some of the best mogs in the game.
If I couldn’t choose mage, probably either warrior or paladin since plate has a ton of AAA-tier mogs too. DKs aren’t really my cup of tea.
As much as I like my shaman and hunters I could never choose either because their mog options are 
Druid. Roar.
BM Hunter…nothing but BM Hunter. Someone has to take care of the critters in game.
Paladin is my favorite class…but I would have to choose warrior. They are just the best tanks.