My proposal contains the following changes from the reference layout:

Major layout changes

Rearrangement of groups

Most of these changes are necessitated by wanting to balance the three columns at the top, and the two columns below (assuming a moderate number of flags for the latter).

Changes to widths of fields

Scope

This is just a "delta" proposal. I'd love to shorten the header, eliminate the radio group at the bottom in favor of directly editing the assignee and status fields, and argue some more about whether the "add a comment" field should be above or below the existing comments. But this is not the place for that.