so we basically swap a player that does not fit into our system with a player that fits into our system. i am totally ok with that.
to the people that claim that diego would have been a better second striker you just need to compare the qualities that both players bring to the table and evaluate which of them are important as striker/second striker:
Dribbling:
Diego is a class above Quag when it comes to dribbling, but you saw last season how far it brings you only being able to dribble but not more
Passing:
Diego is a better passer and creator than Quag obviously, but with our system being 4-4-2 there will not be much need to create through the middle, so its a skill not needed
Shooting:
Quag is a better shooter of the ball than Diego. Diegos shots where most of the time very weak. As second striker Quag will make more out of positions where he shoots just outside the box
Heading:
I did not even see Diego get into the position to head bare even head once, while Quag is a pretty good header of the ball so when we really on the wings to supply crosses Quag is better suited as second striker again
so you see, for the position as second striker Quag IS better suited than diego ever can be