When numbers are low, I try to stick to asking before jumping in on a 1v1. When numbers get higher, the furball grows, and anything goes. I think that's a key here, and part of what has to change as the arena grows.
With low numbers, it's a heightened realism dueling arena.
With high numbers, it should become like a heightened realism ongoing scenario frame, with objectives becoming prevalent again, and more 4v4 type fights.
As we get towards the latter, folks might find themselves forming ad-hoc groups for survival. I know if I take off about the same time as someone else, I try to fly cover for them. Or as was shown last week, sneak out on ahead so I can get gang-banged while they pick off my tormentors, since no matter how even the furball I'll always end up with 3 or more on my tail after a pass or two through it.