Both sides unit should start in each zone closest to defend at mission start.
You have in general the start rush - most prominent being vehicles rushing
to the enemy spawn trying to intercept any other vehicles.
The neat solution is to let all units start inside the mission area
already (aka most distant from spawn to defend).
This way you have a rather fair and intense infantry fight at the very
start about both zones.
And at the same time people can still ESC-Respawn to get both to start
zone to get vehicles.
It does take away the unique start rush element which creates interesting
gameplay situations. Yet more important it solves many issues nicely.