Disagree. I've always voted with the understanding that it hurts only a little. I've never felt bad about down-voting something I just didn't feel I liked. Increasing the penalty would discourage me from down-voting at all.
I have wanted to down-vote something twice in a row though, and found I can't. Considering I pay for each down-vote, I felt that I should be able to say: this is really bad. So, there'd be 1 down-vote = -2:-1 and 2 down-votes = -4:-2. You could limit it there, or let people keep going.
Now I tend to vote without regard to the cost to myself really, it's something I forget about until after the "this is not worth reading" feeling has passed and my vote is cast. Then I notice, oh yeah, I lose a little for down-votes. That might have to be made more obvious if you're increasing the cost, or changing the limit.
Definitely the rep-recalc is something of a "yikes" that could really leave people feeling stung. So that's one big reason not to do it.