I'd rather it was "in addition to" than "instead of." The Youtube description is often good, though you should be able to delete/modify it when it isn't.
You may also want to add additional information, perhaps in how it relates to you or one of the item's other videos. To avoid mixing your description with that of the person who uploaded the video to Youtube, "Description" could be changed to "Original Description" or "Youtube Description" and there could be an additional field underneath for "[Display Name]'s Description" as I suggested here:
You may also want to add additional information, perhaps in how it relates to you or one of the item's other videos. To avoid mixing your description with that of the person who uploaded the video to Youtube, "Description" could be changed to "Original Description" or "Youtube Description" and there could be an additional field underneath for "[Display Name]'s Description" as I suggested here:
http://www.listal.com/suggestion/87