Ursoc was a problem because the biggest damaging ability was the bleed put on the offtank, which means you would take damage all the time, either tanking boss, or not tanking boss. Same problem as with Aggramar. Tanks like DH, Warrior and Paladin work the best when "tank swap" allows them to build up mitigation charges when not actively tanking. Any boss that has stready high damage going on will prefer a tank with 100% defensives coverage. Ofc early Legion warrior had perma ignore pain which was the best mitigation, that's gone out of the picture and good riddance, so sure, we shouldn't compare tank balance with early legion. Also the BFA change "every active mitigation is armor" did a step towards homogenizing tanks, which was not the case in Legion.
I would really hope bosses are designed around classes this time, because Legion saw lots of blunders in that department (pre 7.2 Krosus / Star Augur when some tanks were significantly weaker in magic mitigation capability?)
Still my wishlist for DH would be that some other talent builds would situationally outshine the "1 size fits it all" fracture + spirit bomb build we're stuck with since 7.2. It works well in AOE scenarios but it's quite disappointing there's no "single target" build. For example for DK and Paladin have clear aoe and clear single target talents. Many Uldir bosses have some adds, but that's no excuse to pigeon hole a tank into "you're good as long as aoe is involved".
Anyway most people won't be doing "early progression", if you're raiding normal, heroic, or mythic sub world 500 rank, things are doable with any tank, however some things still might be easier on some tank. But if you feel more comfortable on a class it's worth playing that, as not everyone can play every class at the same level of capability. If you're top 50, maybe top 100, then yeah, probably you're at the skill level you can easily master any class so you pick the most OP one for the current fight. However people who aren't in that bracket often have more benefit from sticking to the class they're most proficient on.
However it's quite curious that early beta feedback (youtube ranking videos etc.) were putting veng DH close to top if not THE top of the tank ladder, but it started crawling down the ranks as the beta was closing to an end. The opposite happened with druid, early vids were placing bear as the worst tank, but it slowly came back to appreciation.