He was a first team player in a team that won a lot, that's the difference. He played almost every game and was a key contributor, the likes of Danny Welbeck were peripheral squad players who won trophies by association. Was he their best player? Of course not, but he did as much as a full back could reasonably be expected to do to contribute. The same could not be said of Welbeck.
Danilo may take his starting position, or he may struggle to adapt to the league, struggle to improve and go the exact same way as Coentrao and end up second choice. I imagine you'd have been saying the same about Marcelo a few years back only to be proven wrong. Either way it'd be good news for us because a top class RB who would be only 24 would become available.
No-one has said that Rafael far eclipsed Coleman. They were similar, albeit in my view Rafael was a bit better. However I merely said Coleman has never performed at the level of our current second choice right full back and hasn't performed at that level against the same caliber of opposition. He wouldn't be a huge upgrade and therefore shouldn't be considered, particularly as there are several better options for the £25m/€35m it would take to sign him.