The problem of too many airplanes, as was pointed out in a very recent mods thread on the subject, is that in some corridors heavy air traffic, coupled with a high rate of time compression, makes planes appear every 10-20 seconds. TMO and RSRDC are attempts at realism. Webster's Better Air Mods overrides those mods realism effects. The answer lies in slowing Time Compression (TC) way down when in the corridors where there is a lot of plane traffic. This enables you to conserve the realism aspect. (At night you can increase Time Compression because planes are grounded usually.)
Here is the link to the mods forum thread.
http://www.subsim.com/radioroom/showthread.php?t=171180 . Note, tomoose's post near the end of the thread hits the nail on the head with his two references to TC (Time Compression), although they are not emphasized. Also, lurker posts are very instructive re realism and RSRDC.
I thought the issue was whether RSRDC caused excessive air patrols. I think I was wrong. I removed the mod, and found there was still a great deal of aircraft traffic in TMO2.0 standing alone.
Bottom line: In areas of heavy aircraft traffic reduce TC. Alternative, forget the realism component and use Webster's Air Patrols.