DPS who are overgeared can usually tank all those lower end dungeons without any problem anyway. If I roll into a dungeon with an undergeared tank I usually just tell them not to sweat it if they lose hate. It's not like they are hard dungeons in current gear.

Also remind the complainers that prae and WP were being speed ran with full ilvl 60-70 groups when they were first released and they have been nerfed since then. If they think a lesser geared tank is a huge issue they are likely just bads.