Playing a warlock has given me a whole new perspective on tanking. More specifically, I can now see how other paladins tank.
I've run into two main types: those who play like paladins and those who play like warriors. What do I mean by this? The second type is best described by this quote: "If I wanted a tank that needs CC I'd have gotten a warrior." They want CC, they do not at all understand or embrace their strength as AoE tanks.
There is another layer of grouping as well, though this is better applied to all players.
1) Players that know what to do.
2) Players that don't know what to do, but know this and are willing to listen.
3) Players that don't know what to do, but refuse to listen to advice, instead saying: "don't tell me how to play my class."
I've mostly run into paladins that are some mix of 1 and 2. They have the general idea, they just need some fine-tuning. For example, one would pull with exorcism, citing the higher aggro. But he listened when I pointed out that with three mobs, avenger's shield will give more aggro overall and he can still follow up with exorcism.
On the other hand I've run into a type 3. He insisted on CC and did not use consecrate. I am not sure if he used holy shield or not, but he got offended when I suggested that he try tanking entire pulls.
Don't get me wrong, I'm not anti-CC. There are times when tanking everything is undesirable. Moroes is a convenient example. Being stunned or MSed is just bad and worth using CC to prevent.
But most of the time CC is just a drag. It takes time to mark. Sure, it might only be 5-10 seconds per pull, but instances have a lot of trash. 10 seconds over 20 pulls adds up to over three minutes. I know, three minutes isn't the end of the world, but we are all human and who wants to wait around?
The damage is lower too. Maybe a DPS in 5-man gear can pull 1000 DPS. But a naked mage with three targets can break that with arcane explosion spam. Give him 6 targets and flamestrike, blastwave, cone of cold, and blizzard and you're going to see a lot more than 1k DPS.
Besides, seed of corruption is just so pretty.