I wonder if the bonus is now "only" a matching bonus of the deposit. As it's mentioned in the screenshot in the other thread
Players before the deposit got a bonus depending of the VIP status of the other site ( also without a deposit) they have been using before but if it's "just" a matching bonus now that's pretty much the same kind of bonus other sites have as well.

Or does the bonus still vary if the player had significant action on a different site?

Don't get me wrong, a matching bonus is still good but it has nothing to do with a VIP transfer so to speak. If a stake gold VIP and a platinum 5 VIP get the same deposit matching bonus then it's not really a VIP transfer anymore. That's why I'm just wondering.