I feel as though this has a good underlying foundation, but leaves me wanting a little more. I know it is a loop and can see if being used to express concern or something of the like. Maybe if you had another 8 or 12 measures with a light melody over the basic progression, you would really have a memorable loop on your hands. Like I said though, the atmosphere this piece creates is pretty powerful on it's own. If you decide to add more, let me know!