+1 I completely agree.
Dantman is right in that such has to be accompanied by promptly reviews.
First problem is, people has to read the RFC. Searching the archive for
'RFC' I don't find it announced to the mailing list.
A RFC could be just text, have some sample code, or a full
implementation in a branch. The time from rfc status to having code for
it could be [0, +∞).
If the author considers it ready to merge and there has been no
opposition in a week, then merge it.
That would solve the rotting problem. I don't think it would be hard to
keep a branch up to date for a week (at least without other merges).
If the code had problems, and took 6 days to fix, or people praised it
from day 1, you are getting feedback, so there are no hard limits.
And please inform us. If you create a new RFC, email the list stating
so. And again a few days before you are going to merge it (specially if
it's an old branch nobody has cared about for months).