Uneven sides in terms of numbers or teams. Keeping the sides even with both walk on players and teams makes a bunch of difference, when one side is uneven it just kills the game. I would say make sure that each side has the same amount of teams playing, with an equal amount of individual players to back them up and fill in the ranks.
Sometimes a team might be very large though so you might have to have 2 teams to match up the size of one teams rosters.
Same thing with the two bases make them different but have equal amount of cover so neither side has an advantage or disadvantage, this makes it up to the Generals to use the cover for strategic value, not just leaving it up to luck of which side gets the better cover.
Have a place on each side where people can take off and adjust their mask on the field safely, it really sucks when you have to walk all the way off the field to just adjust something minor with your mask. Keeping people on the field will make for a better game.