Thank you, everybody! I'm very grateful for all your suggestions and comments. It seems that the jacket is acceptable.
To elaborate a little:
I don't feel "wide" in general, that would be ridiculous, really. But since I carry most of my weight in my tush, I sometimes think that a horizontal line across my hips, particularly where they are at the widest, isn't doing me any favors. This jacket ends beneath my tush, which I think is an advantage seen from behind. I'm not that sure when seen from the front, but as long as it is open, I think it's good.
I agree that this is a useful garment for in between seasons. It CAN be buttoned, and is warmer than my blazers. It does have a wide collar, but it looks better when it stands up. I don't know why I forgot to do that in the photos. The arms are wider than I would prefer, but I think I could hem them. They can't be scrunched, too wide for that. Maybe they could be taken in a little? I think a scarf would be both necessary and useful for several weeks, so it's an excellent suggestion.
Ramya and Harmonica - yes, Goodwill is Fretex:) The sheath is from BR, I bought it in San Diego last Summer.