The arenas in GH2 need to be redone. That much is definite. I'd like for the PC to have to challenge a series of NPC pilots, rather than just complete a series of generic battles.
For the Maquise Spinner arena, here's an outline of how I'd like things to work: First the PC will have to speak with Mullins and convince her to let him fight; PCs who are already members of the PDA can skip this. The PC will then have to fight one or several generic qualifying fights.
Afterwards, Mullins will tell the PC he needs to face an arena champion to continue. The arena champion must be spoken to, then the PC should meet him in the arena on the world map. There may be a subquest involving the champion; this could take place before the match (i.e. if some condition needs to be met before the NPC will fight the PC), after the match (i.e. if beating the NPC will unlock a new quest), or even instead of the match. The PC will be able to challenge the NPC once every 24 hours until defeated. After winning the challenge, the PC can return to Mullins for a reward.
Between champions, there may be additional generic battles. Eventually the PC will reach the grand champion of the arena. Defeating this NPC will make the PC the grand champion and give the big prize.
Problems: If Mullins is killed, the entire arena is derailed. For right now I'm willing to ignore this problem. More importantly, if one of the NPC pilots are killed, this will derail the sequence... I can't ignore this problem. The best solution would be to add a check to Mullins so that if the target NPC is killed, an extra "generic" fight or two will be used instead.
How to enter the arena? For the generic fights, the teleportation method is good. For the NPC fights, meeting them at a shared location would be good. There should be a single arena location that gets shared between encounters. Certain NPCs may come with their own arenas.
Now all I have to do is come up with mechanics for all this. The basic outline can be set in stone, but it would be nice if the NPC champions were randomly selected.
What do you think?