I'm waiting to see what the impact of the linearization of the reward curve will be. The downvote is the the only tool available to prevent over-rewarding at present, but if you use it on certain users you are inclined to end up in a tit for tat war of retaliation, and the down-voter is always presented/seen as an aggressor (even though they are just exercising their judgment on payouts, the right granted by the ownership of Steem Power).