if the follower of a pair is in a heavier category, there is no wake separation requirement,
So that's why we get photos of A380s looming over the A320 they are following?
More seriously, do you (ATC) have any influence over the choice of departure route, in particular when it doesn't increase the distance much? Can you, for example, influence the use of a northerly departure in the evenings for some flights? Or is this entirely the choice of the airline and Captain?