I think that a 2nd price auction model would incentivize splitting the stake of high powered accounts:

Let's say that my account can vote with a strenght of 2000 rshares and there is a post with 2 votes worth 100 rshares. I am incentivized to vote with the same 100 rshare strength. Otherwise my vote becomes an outlier if I vote above or below the current distribution.

If my goal is to maximize my curation rewards it is better for me to split my stake into 20 accounts and vote with an equal amount of voting power with all the accounts on the same post. Or I could split my account in 4 and vote with a strenght of 500 each and turn the other votes into outliers.

Or even better create a high number of accounts with a moderate amount of voting power and turn everyone else into outliers.