Email nor anything related to core email protocols do not need to be fixed or redesigned. It's doing what it was supposed to be used for and still doing it very well. Over the years desktop and web mail people have added too much and its 70s design idea of anyone can send mail to any other's inbox (btw, creative idea at the time worked till 2000s) have cooperatively decreased its usage.
We still need this universal and mature protocol but we should do a different thing for communication. period.
We still need this universal and mature protocol but we should do a different thing for communication. period.