I see what you want to do with the keys which is basically a type of air gapping. Onboarding is going to continue being a pain until we either swing it towards tiered accounts in some way. The problem with removing the payment for accounts in general is the fact we've got named accounts which are worth something in themselves. The moment everything is free the account names will be botted and only trash will remain. But at the same time, while people do want to pay for accounts and get their desired names, they don't all own crypto to pay with. And this is a problem some onboarders come across which is finality. An account is created but keys granted but the credit card used to pay for the account can be disputed and reverse the payment. So your solution could come into play well here.
RE: Strategic Vision for 2023 (Witness Update)