Most of the email I get was written by a human, and requires a thoughtful answer.
However, I have to aggressively fight against not-quite-spam to keep my inbox clean. I'd love smarter filters that can remove terms of service updates, duplicate confirmation emails, work newsletters and the like.
I'd also love to have email highlighted when the time is right. I'm constantly digging up meeting, flight and hotel booking emails on the day of the event.
I'd love to see automatic calendar and maps links added next to each message when relevant.
I say leave human communication to humans. Work on the problems that make them feel like machines.