Viewport strafe while holding middle mouse

Like when you press Shift F to get fly mode --- A and D make the camera strafe left and right; it needs to do this while holding middle mouse. It would make moving around way more fluid. Currently shift + middle mouse drag, or Shift F + A or D does it, but, yeah, it's pretty clunky. I think it would be a really good improvement. A and D don't do anything while holding middle mouse anyway. And you wouldn't have to get ride of the other ways of doing it either.