Wyoming's flag is unfortunate, for two big reasons:
The biggest reason is that this was almost an amazing flag; the red and white borders, the contrast of the white bison on the deep blue. But then they had to go and shove their boring, complicated seal into the center. It's just sad. The other reason this flag is unfortunate is more personal, in that the fix for it is very simple, but others have already suggested it. Over at Your State Flag Stinks, the seal was removed the seal and you're left with a pretty great flag, and I can't imagine that's the first place to suggest that. I suppose I could chicken out and do the same, but flip the bison so I can pretend to claim originality:
In the end, I don't think this looks to bad, but the design of the modern flag (minus the seal of course) is a tough one to dismiss. It can be hard to fix a flag when the best solution is already taken. Not that I'm complaining, I wish they were all this easy.