I find that Improved Devotion Aura, Ardent Defender, and Kings are all pretty integral to our multi-Box tanking needs. The only time I might think about giving up Imp Devo would be if I were positive I didn't have a Tree along, and Kings is still nice even if you have another pally in the raid. Sanc/Kings on the tank and ImpWis/Kings on the Holy is very nice. In such case, both paladins would need kings. Ardent defender is just too good to pass up in any reasonable scenario in my opinion. Just a couple thoughts from a long time Paladin.