I think Wall was omitted because of the Wizards' failures in recent years. Wall arrived with hope, but the team hasn't improved with him in uniform - and unfortunately, Wall didn't make the considerable leap that was expected of him last season. A lot of factors outside his control played a part in that, but he is going to have to put in the work to get better as well.
I agree that he's finally starting to get the real support now, with the team getting rid of JaVale McGee and Nick Young and making the push to add more veterans. But they have to do more in order to get the best out of Wall.
From covering Wall, I think he really wants to be great but he is desperately seeking guidance. He understands his limitations, but he wants to learn. He needs a veteran that he can trust and respect to show how him what it takes to be a professional.
I watched Rajon Rondo go for 44, 10 and 8 last night and thought about what playing with three future Hall of Famers did to help him maximize his skills and perhaps exceed expectations for his career. Future Hall of Famers don't just fall in your lap, but I think Wall would make immediate and dramatic strides if he was with a Chauncey Billups type, who could check him when he's wrong and help him correct his mistakes.
So far, Wall has been asked to learn the hard way. I think he has done remarkably well, considering what he has been asked to overcome and when you compare his numbers to other great point guards, he's right up there with the best. Getting chosen for the Team USA select squad was confirmation of his tremendous talent, but the Wizards have to do right by him to help him improve, help the team improve - & possibly allow him to have a high spot on the pantheon of Washington superstars (whatever that's worth).