If we do go ahead with comments at the bottom of option view, it could be 3 tabs - comment, add pro, add con. With comment pre-selected.
In the same manner at the bottom of summary view it could be - comment, add option. Again with comment selected by default.
And we already have edit, comments and history in tabs in p/c level. If in future it’s in-line edited, could it show in-line comments and history as well?