I think there should be a social alternative to the Guild that focuses soley on PVP.... the Ludis
functions same as a guild - leader, officers, members - but instead of renown, you get infamy points in the pvp pits. Instead of guild ships you get a Ludis training house. You get Ludis infamy points and with them unlock bonuses that work in PVP only. Various spellike wards, speed boosts, weapon boosts, etc effects that would essentially balance PVP. Top level shrines like- Shrine SR45 vs Profane AC +20 vs Light DR/45 etc therefore you can build up your Ludis to grand heights and be the KING of PVP ---- have Ludis wars --- but at the cost of not being in a Guild. Guild and Ludis would be mutually exclusive.
Plus dev can regulate PVP behavor using the infamy points. Ganking noobs? Minus points. Killing over your level, positive points. Winning capture the flag, positive points. etc.
Also, Guild buffs would not work in PVP anymore. It would be one or the other.