I think one of the main reasons for minnow disengagement is their perception that they can write a post (whether it be low or high) quality and have it be under-rewarded. In fact, it's almost a certainty.

"Perfect" curation would mean posts received rewards perfectly in-line with their quality. This itself would be "repressive" to those who adjust their votes based on personal relationships and preference (ie. almost all of us).

There's a middle ground between here and there that we really need to locate.