Any reduction in number of witness votes still helps. Right now we have a system of governance wherein voting rights are equal to SP times 30. SP times 10 is still a massive improvement, but cutting witness votes to 5 or 6 is probably what would be needed to prevent the Steemit Inc. stake from being able to control consensus outright. Not saying they couldn't control 10+ seats still if they chose, but at least they'd probably need to negotiate with some community backed "spoilers" at that level.