A few things, however, it solves a problem I have now in Amethyst, which is that many notes are only "seen" by one or two relays (and without connecting to many more relays listed via NIP-65 for contacts).
Once complete, Amethyst connects to that private relay (and a few others) and it will stream and sync from many hundreds to thousands of relays. Much more than just a few as it is currently.
> a problem I have now in Amethyst, which is that many notes are only "seen" by one or two relays
This should not be a problem, it is how the Outbox model works. Any other additional relay comes from a broadcast from users that interact with the event and this organically increase the decentralization and reachability of user's content.
It seems that you want to create an hybrid client/really, that actually could be useful in edge cases to support "thin clients", especially on mobile.