Ever die right as a respawn wave spawns? Being forced to spectate your teammates till they die is unfun is a detriment to play experience. Nobody likes to wait in the spectator menu when you know if you died a second earlier, you would respawn. Respawn waves should have a 2-5 second forgiveness timer so that if you die right as the wave spawns, you can still push with the team instead of waiting.
Maybe give respawn ticket to those taking or defending on objectives for a significant amount of time?
This ticket would guarantee a respawn if death occurs X seconds after the next wave.
This would help promoting objective play and avoid these cases where the guys who stand ground on objective (att. or def.) don't get their respawn.