I like the shared xp idea, sounds like a great way to lvl up the noobs in the group...
mmm... this suggestion don't require a change on engine system?
Anyway, I already suggested the "sharing experience" system
Yes, but your suggestion is different than mine ; since the party system I'm suggesting handles more than just shared experience.
3) People in your party share experience with you and can follow you on worldmap (With "Do you want to follow...?" window).
If a party is composed of a level 21 player and a level 5 player, the level 5 player almost earns nothing with shared experience, as in any other MMORPGs.