Over all I think it's a nice design. The two toned leather could be considered a nice contrast and it is a good way to use up pieces that might be too small otherwise. It would be easier and a little neater to use one larger piece ( as suggested by bushman.)
If there was one thing I would change it would be the stitching. The stitching just looks too big and crude. The stitching on your bag is a major design element. It draws the eye and needs to be is even and regular as possible. Buckskin items I've seen in museums either have the stitching hidden (sew the bag inside out and then turn right side out when the stitching is done), or just plain had much smaller, neater stitching. Remember primitive does not equal crude! ( I probably didn't have to mention that, but it's a thought I have to repeat to myself from time to time. The criss cross double needle pattern of stitching is a common pattern today, but may not be authentic if you're trying to duplicate a specific tribal style.
Ron