As an element user for about a year: the biggest thing element needs is to make E2E actually work consistently. Every day I see random "can't decrypt this message for some reason" errors, and it makes me embarrassed whenever I convince someone to try using Matrix instead of proprietary platforms and then I have to tell them I can't read their messages and the first three things we tried to fix it didn't work. This is the biggest reason why I want to abandon Matrix for good as soon as possible, and am working on creating another federated chat protocol.