Although what I would really like, and think is long overdue, is an extension to email that normalises encryption and sender verification. It's ridiculous that email can be spoofed like that. (The same is even more true for phone numbers.)
I have a laundry list of other issues I'd like fixed in email, but I'd be happy just to get end to end encryption and sender verification.
> Who can read it today?
It's true that email isn't quite as insecure as it used to be (it was once compared to shouting your message at someone and expecting them to shout it in the right direction until it reached the intended recipient), but there are still many things missing compared to other forms of direct messaging, and there's good reason why many people and organisations don't want it used to send sensitive information.