Prot Paladins get crushed in higher keys. They are genuinely great at almost everything, damage, healing, mob control and utility.
But as a Warrior you are a far more stable tank.
However in M+, Prot Warriors don’t bring much to the table. Excellent mitigation and decent damage, but thats it.
HOWEVER, the biggest issue Prot Warriors have is with community perception. While I won’t sit here and say that they are in a great spot for M+, they are FAR better than people think. This stems from early beta.
Remember the beta? When Paladins, Monks and DKs where the clear cut winners when it came to tanking?
And than the game went live and Demon Hunter tanks where not only the best tank for keys as expected, but also the king of progression raiding because they are actually super tanky, not to mention Havoc being meh?
And then multiple guilds took Prot Warriors to the LAST THREE BOSSES OF MYTHIC progression? And people thought it was only for buffs but on some of those fights they also had an Arms Warrior and they kept rolling with a Prot Warrior because their physical mitigation is exceptionally powerful?
The gist is, Prot Warriors are very solid raid tanks and underrated (don’t confuse underrated with great, they’re not) for M+. And at the level of M+ that your playing in, spec is irrelevant.
Every tank can face tank everything in a six unless they’re playing the spec wrong. Its also quite possible you’re grouping with bad healers and DPS because at that level of M+, well there is a reason a lot of those folks are stuck at +6 and it ain’t because of gear.
You are more than fine tanking on a Warrior. If however, you don’t plan on ever pushing past the 14-15 range, a Paladin is an amazing choice if you pug. Simply put, they have an amazing kit for carrying bad players. Off heals, interrupts/silences for days and excellent damage. Its only at the higher level of keys where a Paladins squishiness becomes a detriment.