I played at a new field two weeks ago that forced the velocity to be between 260 and 280 fps, and their rental guns were set accordingly. Even though I got shot up a couple of times, the difference in bruising and pain compared to 300 fps was dramatically different. I was more likely to get in a fire fight against players of higher skill because even if they over shot me I was okay. At other fields in the area it's not uncommon for the velocity to be at 300fps and to creep up on everyone's markers throughout the day. This facility only allows ramping on the speedball field, but as speedball players would join the games in the woods they tended to forget at first (even though the refs stayed on top of it).
The paint was XO Spectrum low and Formula 13 high grade - also very fresh, and I think the paint can make a difference. The last few times I've used older bags of Heat I've not been happy with performance or the feeling of getting shot. I don't know how you regulate that as a field and make money, but it would seem like more trafficked fields that use better paint while keeping velocities and fire rates lower will motivate people to move and engage more. I totally agree about having good layouts for movement - that seems to be a crapshoot wherever you go, but more often than not the woodsball fields around me are poorly designed (last field was pretty good in that regard too, though).
I grew up on pump and cut my teeth playing pump against guys with semi-cockers and automags. I personally don't have any interest in playing pump over semi again, but I like the idea of giving pump players a velocity advantage for range. Especially if the rental 98s were at 260 and a pump could shoot 300 max, that would be a good way to balance firepower vs. range. While I don't like ramping in use on rec fields at all, it seems like that can actually cap some of the better players that come out to play. Some of my worst game experiences have been playing against guys that can shoot 15+bps in semi at 300fps. I wish that the local fields would cap both firing mode (semi-only) and bps (12.5 or less) when they mix in high skill players with group 1 and group 2 players.
Last thing I can think of is more refs. While I don't think there's a direct causation, I've found the fields that will pay for 2+ refs per field of play tend to better make sure that everyone has a good playing experience. You see less wiping, less overshooting, markers at the proper field velocity that are checked prior to play, etc. This is a tough sell for a struggling field because labor can be a cost fields think they have better control over, but having multiple extra sets of eyes and a consistent ref standard will increase the odds of players returning. All of the bad fields I've ever been on are consistent in having had just one ref for a field or even for the whole facility. Most of the bad fields are in a race to the bottom on price and groupon deals, too - this means more newer players in the area could cut their teeth on paintball with overshooting and high velocities. I don't know how you combat that other than word of mouth for good fields.