Dont want to sounds like fanboy, but ambient light sensor and physical display driver gotta put somewhere, hence why the black bar exist.
I wish they could hide it some where else, inside that super thin metal bezel ? Maybe need some near-impossible engineering to make it happen. When I compare moto 360's super thin bezel against all other thick bezel, I'm happy for the compromise in form of tiny black bar.
I'll repeat again, it's tiny enough to be ignore ( in real life ). It looks big in photos because most of it are close up shots. TBH, I havent really heard any owner complaint about flat tire in forum/website/discuq been huge, most will ignore it's existence after one/two days.
I once use whole black background in order for it to blend in, then got bored of black watchface. Now using plain white background watchface and black bar had not annoy me at all ( if I ever notice it's existence )
My 2cents to anyone havent own Moto 360 and yet claim it's annoy.
it may be because of LG capable of the full face, so expectations of moto to do so will exist no doubt