Wouldn't sock puppet accounts be avoided by the fact that Steem Power is not transferable? A whale looking to divide his holdings into multiple accounts would first have to power down into liquid Steem. New whales I suppose could set up multiple accounts from the start if they have really deep pockets (presumably they could buy plenty of burner phones to get around the phone number validation as well).
Looking forward to seeing your more in-depth thoughts on how to encourage curation, etc.