There are some complications to this.
As explained here (Edit messages time limitation) the creator of the topic cannot edit the post for as long as he wants.
Uses with trust level 0 and 1 can edit posts only during the 24 hours following the post creation; while users with trust level 2 can edit post for one month.
Attaining level 2 should not be too complicated, but it still requires the user to log in the forum in 15 different days; thus requiring at least half a month before they can manage such a discussion.
30 days to initiate and conclude a discussion looks like a good amount of time, however the approval of any feature requires at least one month to be concluded: the voting on the proposal has to be started at least 2 weeks after the RfC and the voting itself has to last two weeks.
Thus, one month to maintain the discussion could not be enough.
Under these circumstances this solution might not be appropriate to deal with this kind of discussions.
Some other possible solutions to keep the discussions ordered have been proposed: