From a healing perspective I find WAR takes more damage than PLD on multi mob situations. So while they are better for burning the enemies down they seem to take more damage doing so. Shield tanks are always better for multi mob unless they do some gimmick on the non shield tanks that either gives them a lot of avoidance and armor (druid in wow) or some fake shield (blood shield dk or stagger on monk in wow, even druid had savage defense which was a damage mitigation bubble) since a shield tank has a chance to mitigate every single attack by blocking it. With 471 Str and 350 block rating they can mitigate up to 44% of the damage. That said I dont find that the adds in this game do that much damage anyway so its not a game breaker but I can tell the difference and might be an issue as the content ramps up.
Well, what I've found it that, I myself, can hold my HP fairly well, even in a multi-mob situation, if I focus everything I have onto my HP recovery moves. The problem with that is, that it makes holding Aggro kinda difficult.
I mean, you have Bloodbath, HP Leeching combo's, and Mercy Kill, and there's nothing preventing you from using all three actively most of the time. When you do, even when you're being attacked by three or more enemies, you can hold onto your HP fairly well, so long as they're none of them are real power hitter type enemies.
However, while you're doing that, you cannot use your Aggro combo's, nor can you spam overkill or flash. The HP absorption rate on these various moves are low enough that you're essentially healing yourself with a thousand band-aids, which means you've got to keep going constantly if you're going to keep up. So, while it's possible to survive that sort of assault with a Warrior with your HP in decent shape, the margin for error is fairly low, and it leaves little room for Aggro. A slight buff to the HP leaching capacity would take care of both issues.
Now to be fair, in a party with a healer, you're not going to play that way. In those cases you break out the HP healing moves when your HP starts slipping, and you want to quickly get it refilled. You could just rely on the Healer, but, this reduces the amount of work the healer has to do.
So, yeah I don't think it's anything fundamentally broken with the class. The HP leeching moves just needs a very subtle buff, and the Warrior Stun move needs to be reworked. Once that happens, I think the Warrior class will nearly be as good for Single enemy tanking as the Paladin, and slightly better for Add-Tanking.
Incidentally, one of the reasons Warriors are better for tanking adds, isn't just that their AoE Aggro move does damage, but also because it has more range. Flash covers more space in terms of volume, but because it's a perfect circle the actual range isn't that far. With Overkill, warriors usually don't have to move very far for enemies to be within proper Aggro distance. Paladins on the other hand, have to move right into the middle of any new Mobs, in order to Aggro them all.
I mean, you can pull a little Aggro with Shield Lob and Tomohawk, but only for a single enemy, and these moves won't hold aggro for long.