It looks fabulous from the nextcloud launched video 4days ago.
Images: could upload the image and search similar or exactly
Talk: Communication over different organizations, similar to matrix decentering chat server, orginzation could invite another person from another organization by /invite:sandra@another_company_domain.com, file shared in the chat own by initial user or organization.
If this features came, most organization or small group could stay away of WhatsApp
Or something else. For those not be able to deploy their nextcloud server, we provide a free server for registration so that would not put many user away.
Talk: Call recording text should be put a name detected by speaker when the person is speaker.
Mail: email signature, email automation for these improvement would be a big challenge at those point are email marketing things.