What are the potential negative consequences?

I think one of those would be, throwing-the-baby-with-the-bathwater effect.

Because some of us minnows still have less than 150sp, and when the voting power is less than 100%, the value of our upvote would be about 0.01 (depending on the price of steem), and it would be unfair if these meagre sign of appreciation we give out to the steemians who take out their time to read our stuff, doesn't count anymore.