While I think it is a good idea to give more opportunities for proposals to be voted by everyone, I still see some problems:

First, the people voting in pre-proposals are the ones really interested in governance. I know a number of players that just cast their votes to get rid of the notification window, without giving a serious thinking about the proposal itself.

Also, more votes will mean more complaints about "endless voting notifications" from players who are not interested in governance.

Finally, since there is no way to show one's opposition to a pre-proposal, it will probably reduce the discussion. People will know it will be sent to official vote anyways (5% is not so high) and they can just skip the pre-proposal and directly vote during the official proposal period. It may have a serious impact as people will have to make a choice with less quality feedback (for or against).