I would love to see Leveling Pact system turned on.
It was very fun to use with my husband to keep us the same level when he was working and I could play.
If you don't remember what it is, it is when you can connect your character with another person's character (as long as they are level 5 or under, I think it was) and you would share you xp. Even if only one of the toons was online and playing, it would store half of the xp and give it to the other person when they logged in so that the 2 toons were always the same level.
I remember that they eventually turned it off on the lives servers too, but it would be really fun to have it back.
It hasn't been tried on these servers has it? I wonder if people would enjoy it.