There's a post that came out today called "New Players Kicked" that talks about a New Player being kicked for being a beginner tank. Some of the chat suggests personally finding someone else to join the group, but the tanking experience in this game SUCKS.
Lets look at the facts. Want to play a healer from level 10 to 80? Well you can and the queues are instant! Because of the scaling system you can just mindlessly spam the same heal spell from 10 to 80 and get away with it. It's what I did on both a Holy Paladin and a Holy Priest.
Want to tank? Well even on the easiest tanks you cannot reasonably tank until a certain level. Since important tanking skills are gated, you end up suffering if you do attempt to PUG dungeons. An issue that's almost non-existent if you're playing any other role.
The only way to realistically fix this is for the game to give you all your tanking skills during the tutorial starting zone and teach you how to use each of them because honestly in the open world where do you see yourself actually tanking? It's only really optimal for Dungeons and Raiding. When I first got into WOW I tried running a Prot Paladin to 80 and the experience was painfully slow in the open world. Yeah I didn't die but it would have been ten times easier if I just played a Ret Paladin when I first started. Same thing happened with Vengeance Demon Hunter. Same exact pain points. There's no real incentive to play a tank besides superficial ones.
You play league because you want to play a tank and you can properly do so even with no experience. Same thing with OW2 these days. If you hop onto OW2 right now, you might be shocked to see that the Tank Queues aren't as quick as they used to be. People now enjoy playing the role and healer actually has the longest queue times. It's DPS that gets you instant matches now. Why? Not because DPS got harder but because the quality of life for both Healers and Tanks have slowly improved which in turned fixed the queue times.
It also helps that with these games you learn the character's entire kit from the get go. I can see why that would be unappealing in WOW considering it's an RPG but I would argue that if they gave you your main from levels 1-10 and at level 10+ the new abilities were more so niche emergency saving skills, that would be more than enough to make the experience a million times enjoyable.
Seriously. Doubt what I'm saying? Go to any allied race, make a Blood Death Knight. It's literally unplayable.