1script - 3:27 am on Aug 14, 2012 (gmt 0)
Interesting idea but I'm curious why you based this on an assumption that Google operates on 14-days cycles ( 1/2 of 28? sorry, could not resist ...) I've had pages drop, then come back up on a keyword and it happened much more slowly than in 14 days. So, in theory at least, you could kill a page that can potentially rank at some point in the future. Additionally, it takes Google some time to de-index pages, perhaps longer than 14 days, and so it seems this 14 days feedback is way too short, can get the whole system out of whack.
If I were doing it, I'd do it with a glacial speed. Perhaps wait for 1/2 year since the last direct visitor from Google comes to that page. But then, it would greatly diminish effectiveness of these efforts.
It sounds like you've been doing it for awhile now, how you noticed anything particular about the pages that drop? Were they shallow content (whatever the definition), duplicates, no IBLs etc. to begin with?