I played a fair amount of Overwatch on the old Steam Controller with a combination of touchpad and gyroscope controls. Touchpad for wide sweeping movements and gyro for fine tuning the aim. It's not quite as accurate as a mouse, and it does take some getting used to, but I found I was much more competitive with it than I was with a regular gamepad, especially when playing games like Overwatch that don't support aim-assist on controllers.
For slower strategy games, using the left touchpad for fast/imprecise mouse movement (or map movement) and the right touchpad for slow/fine tuned mouse movement is also decent. I don't know that I'd want to play an RTS that way, though.