Currently if one needs to change Case properties (priority, milestone, etc.) AND Reply to the case, it takes 30 extra seconds (depending on network connection) to first Edit the case and then go back to Reply to the Case.
Suggestion for improvement:
It could be a configuration option (account/project/ user/as necessary) that Case properties can be edited together with Reply mode. The properties like priority/milestone/assigned etc. could be changed at the same time you write&Submit the Reply to the Case.