If there was a like/dislike button, I would have used it to give this idea the tumbs down.
Seriously though, the beauty of this small community is the richness and quality of feedback that people tend to give. I think a like/dislike button would not add any real value, and may actually discourage people from giving such qualitative, thought-provoking feedback that I and others actually like to read. It's the *depth* of conversation that ties us all together so well.
And people can always add a poll to get simple statistical feedback, if that's all they want.
For example, you could have added a poll to ask people if they like the idea of having a like/dislike button, but I think you'll agree it's more interesting to hear what people think in depth, rather than just yes/no.
Just my thoughts.