it might sound like a weird tactic but if your a captain solo tanking content, you don't really need to worry too much about aoe because your shield-brother will be getting very strong buffs to keep him alive. you will be doing more actually healing if that champ is taking a little damage and with Exemplar you might get dunadains shield off cooldown much quicker if both of you are being hit.
it sounds backwards but compared to other tanks that dread aggro being lost to the aoe guy, you don't have to worry as much.
Level 140: Burg, Captain, Guard, Brawler, Hunter, Lore-Master, Minstrel, Champ, Warden, Rune-Keeper, Beorning