No, most likely we shouldn't improve on that. If you force an end-to-end encryption on all users, you'll introduce an extreme inconvenience for users so they'll have to do things like identity verification of their messaging partners, do fingerprint matching, and also lose the capability to easily sync messaging history between different devices. Or you could skip on major inconveniences like identity verification, turning your encryption into a security theater [0].
99,9% of users want convenience and a warm fuzzy feeling of being secure, they don't want to exchange keys and do other nasty stuff that real e2ee requires of the. This was proven in force by Durov, who just promised that his app is the most secure ever, while, in fact, all regular messages in Telegram are unencrypted (except so-called secret chats), and I'm yet to receive a secret chat request in telegram from anyone.
