I think he's been moved to CM as he can't really play the dual 10 role personally, you need to more of a dribbler/converted winger. He has been much better as CM than AM.
Yes, I disagree, and I don't think there's a huge difference in actual technical ability between most of the players you reference, there's a bigger discrepancy in how they are being asked to play. Amorim's system is known to us, we can clearly see his plan of how he wants to play out and the CM pair is not the issue, it is the CBs. Ugarte/Morita for example is not an amazingly technical pair, the problem is currently we do not have a CB who comes out into the midfield which is what he did at Sporting. That creates the extra man, as it stands Ugarte and Bruno are almost always covered by 3 players and both have been poor in possession. Any team with a half decent press just waits, as Spurs did, as Soton did, for the ball to go into Bruno/Ugarte or go top a WB and then hounds them. That won't change by simply spending more money on a new CM, it will only change if a CB steps out or, although clearly this won't happen, we change formation.