PvE sounds very cool, especially with Zone's theme, but I'm not sure it would work very well with Zone, let alone any Graal game. I definitely think Zone should embrace the planets, though, and make different terrain there. Maybe it can focus on bosses with actual quests to help get baddys involved more. It would actually be cool to be able to tame some of the friendly aliens from other planets. HINT ALERT You could require different levels to unlock taming different aliens/creatures. Then there could be alien battles with your tamed alien pets and it could be a new spar theme basically.
Oh god. I just realized I just described Pokemon. Oh well, almost anything would be cooler than what Zone is right now.