4 in a row?
Consecration (As laughable threat as ever) 30 sec CD, 10 sec duration
HotR 3 sec
Holy Wrath 15 sec
Avenger's Shield, unglyphed 15, variable with GC procs

Vs.

Blood Boil, 1 blood rune
Death and Decay, 1 unholy
Heart Strike, 1 Blood

I don't see a serious difference.

Bears might have an issue with the CD on swipe, but I have yet to see a bear have trouble with AoE. Unfortunately I don't currently play one endgame to comment further.

If a bear uses Thorns correctly on a pull, there is no way he should lose aggro. As long as each mob in a pack hits the bear just once, the amount of damage and threat from thorns should easily keep those mobs sticking to him. If swipe misses and a mob aggros to another player, he has faerie fire, and, failing that, growl, as ranged aggro abilities.

Honestly it feels like most tanks are pretty much equal with AoE threat; pallies are still slightly better solely because of avenger's shield, or the avenger's shield + consecrate combination. When doing 5mans on my fury warrior, I've been able to pull off of pally tanks about as much as I have from DK's and warriors. Don't run into too many bears to know, but IMO bear threat is all about thorns.

Also, if you have a druid in your group, and she's good at casting thorns on the tank, AoE aggro will be ridiculously more easy for your tank to maintain.

For comparing Paladins and DKs, Avenger's Shield and Consecrate are along the lines of Heart Strike and Death and Decay. After those you're looking at Hammer/Holy Wrath and Blood Boil. I'm not sure how they stack up, but one of those two is the wild card. :P

Oh, and if Paladins use those four abilities in a row, they're either doing it wrong or trying to recover from someone else doing it wrong.