An irritant of mine would be spawning directly on top of or near another player. I know that this problem isn't exactly new to FPS's, but it's still a nuisance none the less. I believe a way to reduce these occurrences would be to have more spawn locations.
Another spawning issue that I would like to bring to light occurs during Team Reaper matches. If one team corners another, the trapped team members constantly respawn next to their caged teammates, basically keeping them trapped. I hope that like Modern Warfare after a certain period of time the game will start spawning the trapped team on the opposite side of the map, causing the team bases to be switched. Being screwed over by the computer is absolutely ridiculous.
Remember those in prison as if you were their fellow prisoners, and those who are mistreated as if you yourselves were suffering. Hebrew 13:3 (NIV)
I don't see the problem. If you are cornered in an area, take another path out. I've done it many times and I hate how COD changes the spawn points. As soon as the battle gets good, COD decides to slow the game down by spawning you at the other end of the map. Also, you have a few seconds of invincibility when you spawn, so again, I don't see what the problem is.