Not taking the whole thing as in-depth as some people (and I'll admit to being one of those people who just 'suggest' barely thought out ideas) but the one thing that came to mind regarding the issue was a system where voting, say, 0-1-2 would make it a requirement to post a 'reasons why' beit through the review or whatnot.
This wouldn't stop 0-bombing or downrating in general, but it may put-off the type of people who just want to click a 0 and move on without interruption... May or may not fix much but it might throw the lazy voters off if they realise there's suddently a requirement for voting an extreme end of the voting spectrum (Again, I re-state, this hasn't been thought out and has either a) been suggested already or b) could quite possibly be a useless idea /shrug)
Personally I don't see why people wouldn't ask why that shouldn't apply to voting 'anything' as, like people already know, folks are quite capable of insta-pressing '5' vote daily on their own work, too.
I kept a check on my own song today (was released a day or two ago) and at one point it had leapt from 5.00>3.00>4.80>3.80>4.00 and I'm sure it'll keep spirally to the extreme, one way or another, until there's too many votes for low-end voters with no vote-power being able to push the vote anymore than 0.1 in which case you'll have the happy medium, whatever it may be (2/3/4) and thats ultimately where it'll generally rest without excessive votes.
Would it be right for me to religiously spam '5' on a daily basis, knowing there's probably some sad-sack out there doing the same with '0' anyway? I'd like to think I wouldn't have to as I don't like the ideo of self-voting anyway as it defeats the entire purpose of votes, and thats to get an outside view of how your work is generally percieved, though in the state it's in, this is impossible anyway.
Review wise, again, not many people are inclined to take the time to review things and the large majority I see on people work are either cringe-worthy one-liners "OMG LOEVSD IT MAEK MORE :D :D :> ^^" and the occasional long, constructive review that some dolts out there click as a 'Useless Review'.
Honestly, as someone relatively new to the audio side of NG I haven't a foggy notion of what could possibly contribute to helping with this, other than maybe taking some more time to give constructive reviews to the work I enjoy on NG and hope it makes a good example for the others who read it and encourage less hate and negativity but, hey, we know nothing like that will ever stop people who can freely zero-bomb everything in their attempt to mould/pave their way to the 'top' charts or simply because 'they can' and the same applies to self-voting.
It's nice to at least have a discussion thread for the matter, however and who knows, maybe something will become of it ^^