I have been playing a lot of PvP in game recently and have a few ideas I would like to share.
Ranked PvP code of conduct- Similar to the one on league of legends, helps prevent players from leaving games.
Cross Server 8-8 PvP Tournaments- Could be random maps, or it could be specific hutball tournaments, voidstar, etc.
Capture the Flag- I feel like capture the flag would be a really fun game type to institute into this game and could be easily added in.
Arena PvP 2v2 and 4v4- Could easily be added in and would be incredibly fun. Could also be used for cross server PvP tournaments.
You could alternatively make a separate Tournament PvP server people have to log onto where every player receives max gear and level and dukes it out with their team against evenly geared teams.
By having weekly, or monthly, or bi-monthly tournaments you create the potential for competitive players that play with their 8 man team practicing and preparing for the tournaments.