A properly geared DPS Paladin can easily top 220DPS(Actual) and that's before full 90 gear/DPS accessories, while still tanking his portion of the fight, stoneskinning, and stunning birds. Two tanks aren't needed because the adds are there for no reason other than someone thought the fight needed adds, but that doesn't mean that another class with a lot of utility isn't useful for other things. A Paladin/Paladin setup is also still going to be better until you can (safely) maintank with the Warrior and that's really only because Warrior seems to do a bit better damage with Defiance up vs. Paladin with Shield Oath up. This doesn't take into account the fact that a Paladin could also wear some DPS accessories while maintanking or full tank gear and use Sword Oath in which cases the Paladin would do more damage and still have more surviveability.

The videos I've seen of one tank looked overly complicated and were slower than 2 tank kills.