Allow control of whether comment field will be shown on Edit and Transition screens

In our JIRA implementation editing of issues is only allowed for privileged users who don't need to justify why they're making a change. We have a lot of fields on our edit screen and even with tabs it's a bit cluttered. We'd like to be able to nix the comment field on the edit screen to save a bit of screen real estate and clutter. A drop-down on the Edit for a screen to enable or disable the comment field would be nice... it could even be combined with http://jira.atlassian.com/browse/JRA-4972 to a single drop-down as follows:

Comments:

Disabled (Ability To Leave Comment Does Not Appear On Screen)
Enabled And Not Required (Comment Is Optional)
Enabled And Required (User Must Leave Comment)