This is the problem I have teams buying attackers for the sake of it, do United not already have a very interesting attack? Rooney, Nani, Valencia, Young, Welbeck, Hernandez..... are players like Hazard really going to add that much more?
Unless a team has a problem scoring goals I see very little need to add more and more attacking players just for the sake of it, I said the same last summer when Barca brought in Sanchez and they broke up the winning formula of the previous season when what they should have spent their money on is strengthening their defence.
Man Utd dont need anymore wingers/support strikers we need to address the area of the pitch which is lacking and that's in central midfield. Get some dominant players in there then it gives your already more than efficient attacking players and even greater foundation to create and score goals.
Players like Hazard and Kagawa would transform our attack from one dimensional wing play to restoring our across the pitch goal threat.
Of course, the same would achieved by buying and then playing decent mobile center midfielders.