So yeah, just before Rick says the solution, I just wanted to make sure I got the problem right… Problem is a fact of balance. If you’re shooting with the mouse, you click and shoot at an specified range, and that’s it. If you shoot with the controller however, you might either have a bigger range, and/or be harder to aim.
I think a solution to the problem might be letting the player to “charge the shot”, so while you keep pressed the button, it shows you a helper.
It will still help you a little with precission (I’d say, within a cone of 5º or so).
Finally, the shot’s range will correspond to the range of the attack. So if you shoot with the mouse from 5 units, the shoot will actually travel 5 units (maybe a little more, but not too far away). Also the helper would correspond with the distance.
So yeah, that’s what I came up with.