"A druid is capable of holding AoE aggro, it doesn't matter which one is capable of putting out more AoE DPS."
That's an opinion. I was hoping for hard facts.
Everything you posted was an opinion. And no, a druid is capable of holding AoE aggro. That is a fact. It doesn't matter which one is capable of putting out more AoE DPS. The druid either has threat or he doesn't and the DPS don't care which one is doing more DPS. That is also a fact.
Paladins, warriors, druids and monks all take less damage than death knights (assuming proper play). Death knights, however, heal it back and have a higher health pool to compensate.
They generate more threat than druids imo because of the 6 second cooldown on thunderclap along with the frontal cone shockwave. What does a druid have that can match that?
They do not generate more threat than druids. In fact, druids are ranking higher and doing more damage on log parses than warriors.
This is also wrong.
Death knights have high AoE DPS, but the fact is it's not high enough to be a significant difference. Also, monks trump them. (Any DK that's armying on non-challenge mode trash outside of a clutch situation needs to be shot, btw.)
Which tank is exceling also depends on the type of content you're doing.
You can't give advice based on opinions. The main differences between tanks at the moment is playstyle.