How can you say McCarthy isn't a destructive player? He's at his best breaking up opposition play and hounding their midfielders, winning possession and passing it on to our more creative players.
Cleverley is more than capable of a box-to-box role, in regards to his power and stamina getting him up and down the pitch at pace.
This Mirallas/Deulofeu love-in needs to stop. Their both class, yes, but unfortunately just don't show the level of consistency required to demand first-team spots on a consistent basis.
Del was brilliant against Reading and West Brom, but then was poor in the derby. Mirallas has been unlucky, but didn't help his chance with a stupid red.
I expect them both to play plenty this season, but it's horses for courses and it's very understandable why Martinez would view Cleverley as a better option to provide the side with balance.