I am glad to see that someone else noticed the sad matter of "downvoters", as you call them. Those guys really driven me on a bad mood lately, I admit that. The bad thing is that you can't say them anything because they also feel "offended", well ok doesn't matter anymore.
Btw redon there's no need to expose them, I have a complete list of those guys, if you wish ;)
If I can tell my opinion, I still think that the better solution is to have 2 rating system from 0 to 10, users and admins ratings. But there are alternatives also.
A solution could be the one that is applied on some olympic sports like diving, where the lower and the higher votes are discarded, the rest are summed to get a more "balanced" average.
Another solution (a bit drastic maybe) could be inhibit the exposed downvoters to vote again, for a limited period of time at least.
Seriously, apart from voting systems, all we really need is a bit of common sense, honesty and "fairplay", and a pinch of humility would helps also. To get upset because a map is not taken for release makes no much sense, since only eirhul and few others have the last word about that.
It's normal that we think our maps are good ("god" in misanthropx case ;) ), and it's normal that our friends thinks the same and make everything to give us help with rating. The more the friends the better the score, this makes things unfair as I already said elsewhere.
Someone talk about votes for aesthetics, geometry, texturing and so on, but there's a very important parameter that has to be considered in order to give a fair vote: the effort. If we begin to consider "efforts" that people produce when making maps as a valuable parameter, we can rate work of others in a more fair way. This not means that efforts always produce masterpieces of course, but that could avoid a lots of downvoting in my opinion.
We have just to keep in mind that, whatever the vote, only admins take the final decision. Of course admins, for the high position they have in this matter, have to judge/evaluate maps/contents responsibly, with rigid objectivity criteria.
Wishes.