Well, we’re here for two reasons. Initially they tried to slot in tanks as a replacement for healers and gave Paladin tanks their own mirror ladder because of their advanced healing capabilities which would’ve given them a notable advantage over most other tanks.
Then there’s them restructuring shuffle to feature tanks as dps with a limit of 1 per lobby.
We’re now in a place where it’s probably possible to put Protection Paladins in as any other tank which alleviates the whole healerless lobby frustration as well as the potential issues with an isolated mirror ladder.
If they stall out games too long or whatever they can always have their healing output (or other numbers) further adjusted.
This is all operating under the assumption that they’re unwilling to outright disable particular specs.