Everyone pretty much hit on good points about this field idea. But there's some things you have to do, to actually attract alot of airsofters, to make it worth making a new field. (I.e. first couple of games you host, are free!) Another good idea, would to get a couple people that have airsoft experience and have them try come up with a floor plan. Mis in alot of things, like imagine the terrain that we would most likely encounter overseas. A good idea, would be a small spot for CQC, as alot of airsofters love CQC, then there's those who like a bit of distance. Throw in some vehicles, trenches, and walls, and you're nearly complete!!
To those complaining about getting paint on your gear, simple fix!!!! Don't lean on the paint!!! Easy as jumping down stairs, you just don't jump down more than you can handle. For those who want to try flame me... Think... MilSim, you think people in combat are gonna complain about leaning on a wall with blood on it??