In the "Edit Item Listing" form, the "Extended Description" area could use a preview button. If not there, then at the bottom of the form next to the update button.

That way the store owner doesn't always have to "Update" to see if it looks correct before having to go back to the Edit Item Listing form to fix any formatting issue. This will ensure the Extended Description looks professional all while still in the Edit Item Listing area before it goes live. While you also don't have to go back and forth from updating several times to make it look right.

Oh and as a bonus, a preview button does exist but subjectively its in the wrong place. Said place is in the "Manage Listings" area, but a bit useless there when you need to actively use at it as you're editing. Plus you don't need to preview everything (up to LL on this), just the content that would go into the "Details" tab of the preview since that would be the most feasible use.