You can do batching right now, just send 100 nip46 requests without waiting for the replies and you've got the batch - you pay 1 RTT per batch. We discussed this once on github, IIRC nsec.app was able to do ~50 decrypts per second. Unlikely to get much faster, 90% of time is spent verifying signatures of nip46 requests etc.  

 Ok now that I'm thinking about it, the signature verification overhead could go away with batching, maybe it could make sense.  

 I would imagine it need a new batch command right?

sending a bunch of request as a hack probably is a lot less efficient