Perhaps less than two months is too soon to judge but I do see a pattern suggesting there is an impact. If you're telling me the nominators have no limit on how many stories they can have boosted, I'll agree with you. If I submit to an editor who reaches his/her maximum and cannot make further recommendations, how can that have no impact?

You didn't address the suggestion that there be some minimum standard that guarantees a story to be considered. I don't mean to be argumentative but if your successful writers are saying they think the process is hit-and-miss and restrictive, it's worthy of consideration.