I generally agree, but I wonder how popular cloning wallets between devices will be in future. Right now if someone wants to have a wallet shared between Hive, blockchain.info and Bitcoin Wallet for Android, we just tell them they're out of luck and they need to pick one, or split their funds up manually.

But probably a lot of people would like to use different UI's to access the same wallets. Sharing key trees is a part of that, though full blown wallet metadata sync would also be needed.

So I guess we're going to end up with some kind of fairly complex compatibility matrix. But I agree it may be unavoidable.