For me I would be very happy if they go back to the bf3 (or bf4) format. I do not really care about more levolution or more players. As I rather have good gameplay, and more players will not ensure better gameplay imho.
On bf4 I enjoyed the 32 player servers the most, depending on the map of course. Metro 32 players is great, 64 players wasn't that great. But on the bigger maps I liked to have 64 players.
I will be happy with anything modern again. BF3 and 4 would great. Would be interesting to see if it goes to 128 player servers. Shouldn't really be a problem as long as the map size and balance is OK, but would also expect smaller servers to be available with certain game modes.
I still prefer Rush over Conquest tbh. We only ever ran Rush servers for BFBC2 and then somewhere along the road ended up switching to Conquest...probably in BF3 days.
I was thinking maybe it would be worth putting a BF4 server up on the run up to BF6 release. I would expect a fairly large increase in players during that period, so might be a good way to attract new members. Who knows?!
I want the opportunity to have squads and platoons, so the gaming community can (again) contribute. And deicated servers, where a clan can kick, make rules, etc. As far as I am concerned BF3 and BF4 are the two best of them all.
I miss BF3/BF4 days, that's when the clan was at it's best. We need this back again, dedicated servers, squads and platoons, Commander like in BF2142 where you can play and command, and a few beers on a Friday night