Go ahead and see it, if you haven't yet.
For an observation about BB-8's design, head under the line. I won't say much else.
So, one of my coworkers got one of the little toy BB-8s--the one you can drive with your smartphone--and noted that it tends to pick up dirt and dust from whatever floor it rolls on. This would clearly be an issue for any real droid built with this design. The whole thing seems, at first, to be somewhat impractical...and it is certainly improbable that this thing should get such good traction even on sand.
But it soon became obvious why the droid was built this way--he's far more mobile than his predecessors. He can keep up with running humans far better than any of his droid predecessors ever could, and for this installment, they needed that.
So, okay, I'll accept the design.
Arright, that's it. Y'ain't gettin' any more from me about Star Wars until at least New Year's.