I'm not convinced the problem is either - it remains to be seen for me.
The players should be good enough. Despite the (somewhat justified) slagging off of Milner and Young, they are both wingers for the two best clubs in the Premier League, and at 2 of the top 6 clubs in the world. Questioning their quality is foolish.
Whether these players perform for their country is the big issue - Rooney for one feel far short of the standard we expect from him.
I think Roy did a great job considering the time frame and the history - In the time he had, he could do little more than make sure the team were organised, and defensively solid. He achieved that brilliant methinks.
what he couldn't do in the time was progress to attacking fluidity and ball retention. These are things that will come, and I've no doubt he'll tweak the players used to include the likes of the Ox and Wilshere, changing the way we play.
I mostly agree with cleanprophet's assessment - the tactics weren't making the most of the key players. For them, it was a backwards step. Milner struggled somewhat in Mancini's first full season at City, where he concentrated on defense (very well as I recall). With the resources of the club, access to whatever players he fancied, and 18 months full time, Mancini progressed nicely. Young moved away from Villa to get away from the 'survival' mentality, and slotted straight in the United's 'winning' mentality, showing he can do it at the top level. Roy has done the first half in a few games and a few weeks; but was never going to manage the whole process in the time he had.
It remains to be seen if he has time to complete the mission, given the number of games he'll manage part time with little player access, but the team spirit and togetherness is definitely the right start. I'll be looking forward to what he does in the next game - and I'll be disappointed to see the same team player for the qualifiers. We need to blood some young players in competition, not just friendlies, and to do that properly we need to take some risks in qualifying.