Perhaps a more interesting solution: Make article points equal the total number of points in comments. (Naturally that's not a perfect solution either.)
It might be useful as one factor in a complicated score function. You need a factor that diminishes the score over time, too, so it can't be quite as simple as you describe. In general it seems like you don't want a comment saying "This is as insulting as it is factually incorrect" to count as an up-vote.
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[ 2.9 ms ] story [ 24.0 ms ] threadSometimes I make 3 or 4 comments on a submission that I wish I could down-vote it.