This is just philosophical issue, but I'm interested what you are thinking.
A lot of developers posting new plugins and releasing upgrades every day. And, ofcourse, all of them what to do the best they can. We, as WordPress community can help to improve his/her work by posting bugs, possible solutions and recommendations.
And the future of a good plugin depends on how many downloads and how many people are interested in it.
Most of us take in consideration few parameters:
- last updated;
- How many people said It Works or It's broken
And if there are broken votes, some people will think twice. And this reduce the download speed.
The problem of this voting system is that you can easily vote that "It is broken" without leaving any kind of message "Why it is not working."
I'm guessing that sometimes, competitors voting against each other or somebody, by mistake, clicked a wrong button.
So my suggestion is to add a input field with an explanation - "Why it is not working on my website".