Neither.
We'd be a better team with Colwill at 10, but he's a luxury that requires two other midfielders with more of the qualities that I list than our current options and wide players who work their socks off (Willock and El Ghazi have barely broken sweat all season). This is how teams can accommodate an attacking 10.
Look how average Man City look now that Silva, Gundogen and De Bruyne's legs have gone and they are missing Rodri's physicality.
So, I'm going to say it; Colwill is one of the few players we have who has the ability to rise above our current malaise but the imbalance (a kind word for crapness) of the midfield and the wide players makes it, on times, right to leave him out.