I have an alternative approach. Since account creation and asset creation brings most of the fees, why not to leverage that first?
- let's start with assets, switch to pricing model similar to domain names... asset creation fee pays it for e.g. 1 year, then you need to renew, assets are being create mainly by businesses so it wouldn't annoy ordinary users; some safety measures would be necessary so that e.g. you cannot "steal" an asset name that issuer forgot to renew; what to do with prefixed assets etc.
- decouple private keys and account names... similar to first point, human-readable account name is a service that you need to renew annually; users need to be able to get their funds back after their name expires
- if still not enough, focus on trading fees - increase flat order creation fee; optionally it could become a part of % trading fee of assets (i.e. user would pay 0.2% fee on order creation when purchasing OPEN.BTC, the flat fee would go to network, rest to the issuer, it would be easier to understand for users, for businness it would be one of their costs)
- if still not enough, focus on existing worker proposals