A suggestion I would have for the Vasari Loyalist "To the Core" ability is that it works on unowned planets as well as planets you own, pending balance. Otherwise, when the Vasari Loyalist fleet decided to get up and abandon planets, it would be nigh impossible to colonize planets for draining them due to hostile culture (which thematically doesn't make sense - if you're stripping a world, who cares what the locals think?) and the lack of ability for the Vasari to spread / repress culture themselves. As for hostile planets, well, we have the Evacuator's lvl 6 ability for that, which if you have a nice sized end game fleet, you could have a couple.
Bear in mind I only play vs. the AI, as I don't have time to invest a couple of hours where I can't pause / save and pick up the game at a later point, so I can't speak to the different dynamics of multiplayer.