I understand, and really it isn't significant, but respawn zones prevent blue team from respawning at the red team's flag. What I would do is cover most of the map in red and most in blue, allowing them to overlap in the middle, but preventing either zone to cover deep into the other team's side. That should help in reducing spawn killing, while eliminating respawns directly by the other team's flag.
I'll take your advice and bring the respawn zones up to those spawns on the lower section of the bridge. I'm pretty busy with another map atm, but i'll try to test it out this weekend. Hopefully this will resolve any potential issues of this kind. Thanks for the idea/feedback