My gut feel is that your example of the voting system tweak will make users like me might not count. Granted, I don't comment nor contribute directly by providing links.
I have various reasons for my silence like the fact English is not my first language (nor even my second language, so it takes me forever to compose something in English, and I still run the risk of my comment turning into grammar crit, with the point I try to make being lost in that noise), a lot of people on the site is intimidatingly intelligent, my points have already been made, etc, etc.
But. I do vote. Due to my non-existent karma I cannot downvote, only upvote. It's limited power, but I try to use it wisely. I cannot downvote the horrible negativity I saw, for example, in the wikipedia design thread (a submission I found fascinating even though it was flawed, as it was lovely to see how their thought process worked as they redesigned the visuals), but I did upvote one or two comments that I thought were thoughtful and added to the discussion. I would like to believe that I made some difference to the tone of the thread, even if it's in a very limited way.
Those that see the world as all shades of gray are not generally very vocal - you don't see a vocal middle ground in most arguments. But this doesn't mean we don't exist. And I don't know how "negative" comments will be classified, and I think people like me run a very real risk of silently becoming false positives when we stupidly upvote things using our own dodgy rules.
So - please consider unexpected side effects such technical things introduce. I guess what I'm saying is I'm already put off by some of the unwritten rules I perceive on this site, if the voting system is also rigged to make some people silently powerless I don't see how to be useful at all. It is off course your prerogative to decide that my type, the silent-but-voting user is unwanted, and if so, that's fine. But I hope I contributed something from time to time.