HF19 did reduce the advantage large holders of SP had, because prior to the fork that SP weighted votes exponentially, and the fork reduced that weighting to a linear model: one SP, one vote.

However, at the same time the fork reduced the labor required to fully drain VP by 400%, making it far easier to extract maximum financial gain from the rewards pool. @aggroed estimated that HF19 improved the situation by reducing the concentration of rewards in the author rewards pool to 93% of author rewards going to a handful of accounts (high SP holders) from 99%.

It may, however, not be quite so improved as that, due to the reduction in labor (and therefore time) necessary to fully drain VP.

Edit: I wanted to add that this also reduces the number of votes minnows cast by 400% as well, dramatically reducing the rewards minnows deliver via curation. This also dramatically concentrates the rewards pool in the accounts of high SP holders.