i totally agree! yesterday i saw someone's post criticizing a heavyweight downvoting their content merely to eliminate the payout on a couple of other posts because of some personal animus and then that post being downvoted onto oblivion. a system that allows that kind of inequality won't survive the potential influx of new participants. downvotes shouldn't be weighted the same as upvotes, them should become disconnected to steempower and count as one for one
Some other thoughts I've had are that downvotes should cost the voter proportionally the same amount, or numerically the same amount. I don't think either will happen, but changes like this would still enable stopping spam and plagiarism, while making downvoting just for personal reasons less palatable for those doing it.
I reckon downvotes just aren't necessary except for spam and the like, and those can be handled by groups of spamcops.