The issue you are describing is that self-voting whales will now be waiting until the "early voting penalty period" is over, which will increase their rewards from self-voting because other users will be front-running their votes.

There are two possible scenarios:

1. The amount they will get from this is more than the curation rewards they would currently receive by self-voting as soon as the post is created.
2. The amount they will get from this is less than the curation rewards they would currently receive by self-voting as soon as the post is created.

If 1 is true (which is what you are asserting) then they can already do this today. This change is not enabling any abuse that is not already possible. Steemit could exclude the proposed change from the hardfork and all the self-voting whales could start doing this to increase their profit.

If 2 is true, then they will be making less under the new system, so there is no issue.