Sorry to say that it is of the most upmost importance to the central theme of mapping and that it doe most definately belong in this forum as much as you dislike it.
Mappers can (and should) use the tools to change game play if the mod has a problem since releasing a map takes a day or so for a decent one and paches (which the public has only marginal say in) take months. Addressing these problems with work arounds is key in map development and developers should be open minded to new ideas; especially ones that are weathered to development.
I am working on a AvA co map and was toying with a similair idea about the doors to alter game play a bit around the hives on a timer delay.
Basically they are time sensitive and they toggle open/closed every 30 seconds for 30 seconds.
This prevents lame spawn caming and promotes rushing as a team. The only other way (mainly for reg co and rine V rine) that I thought might be to have 1 way teleporters that you use after you spawn, allowing ppl at spawn to group up and acctually defend com chair.
Primarly we are on the same train of thought 6john6doe6 in that timered doors can help. I definately think you should add some game text entities and seethough doors so that ppl who are new to the map get a fair warning.
I heard that you can affect cvars by plugins though from maps:
http://www.modns.org/forums/So a map script might be able to turn off the timer with the right coding.
I agree that the timer is as lame as the free experiance aliens get and that mappers need to address this unbalance in their designs.