Yes is not all that helpful - if there are issues with the functionality of the interface (something broken) then I would suggest you compile a list of everything that is broken and send a bug report to the mail team. In mail, at the top right, is a pulldown for "help". In that list is an option to "Report a Bug" - use that to report the bug.
I would suggest providing real information on the problems of mail instead of just saying you dislike it or it will probably be ignored.
- Jon