One of his biggest assets is also one of the things that might expose him the most, that is the willingness and (sometimes) the abillity to defend on the front foot, trying to intercept the chance.
Will see him rinsed every now and then, but also being very good now and then.
He isn't top class though, at this moment in time I rate Rojo and Bailly above him and Jones about on par with him. He is probably just as good a defender as Rojo on abillity, but Rojo has the mental edge over him imo.
Reckon he would be good for a bit smaller team than us that is expected to have their backs against the wall more, but for a team that wants to be on the front foot he is simply not good enough on the ball.
I am all for defenders being defenders first and foremost, but you need to have atleast a minimum of skills on the ball, and this is where Smalling falls short.