I'm not an Oilers fan. I don't even think Oilers fans are Oilers fans at this point (this is my favourite Hockey video from last month:
http://www.youtube.com/watch?v=8DIFeOkD_dc ).
I watch the guy plenty though, and his speed and finish is undeniable - he's also an underrated playmaker. His play away from the puck is weak, but that's not why you take him. You take him to put pucks in the net. Taylor Hall playing 14 minutes a game isn't going to lose the tournament for you. He's absolutely comparable to Ryan - they can both be game breaking players, but the difference is that Ryan's weakness, his foot speed (which is of increased importance on large ice) is Hall's biggest asset. So their rationale at least makes some sense, and even so, I think it's ludicrous that they left Bobby Ryan off the USA team.
Re: my lineup, I'm not exactly worried that if you put Hall out with Stammer and St. Louis that he's going to ignore the fact that he's playing with the reigning Art Ross winner and possibly the most lethal scoring threat on the team and try to do everything himself. They'll get the puck. It makes far more sense to me that in attempting to defend against those two players, the opposition gives Hall too much space and he skates right past them. No matter who your defense pairing is, they have to be nervous about facing that line, and if you send your best against them, who's going to stop Crosby and co?
Also, note that in any event his spot is easily enough filled by Duchene if he's not working out there. EDIT: after thinking about it, you know what I compare this rationale to? If Russia had decided to pass on taking Bure to Nagano because he wouldn't backcheck.