There are several ideas being floated around. One would be to simply not have a global trending page. You could still have trending "per tag". Another would be to have trending linked not to rewards but to views×votes (regardless of rewards). A third has been implemented, a bot (Steem Sincerity I think) that comments on posts with high rewards from bots and informs readers that the post "trends" artificially thanks to bots. A fourth is the SMT thingy that's in the process of being implemented where you have several currencies, one per community if I understood well.