I don't like change. But I guess it has merit. (An answer downvotes graph would help to judge it better..)

Usually I avoid downvoting newcomer questions. It's pointless to downvote a rep 1 user. And if it costs me -1 without affecting that account, I do in fact opt out. (But most people use closevotes in lieu of downvotes in these cases anyway.)

So making that free would indeed incentivize me to downvote more questions. But I believe I'm already downvoting too few answers. And if this idea is given a roll, I would request that this is used to at least even out the discrepancy between question and answer votes:


                   cost  upvote      cost  downvote

     question      0     +5          0     -1 

     answer        0     +10        -1     -2

If upvotes only bring half as much reputation win, then downvotes should subtract only half of what answer downvotes do.