This is so interesting... as a person who also has had much symphonic experience, we do use visual cues from a conductor, but by performance (or studio) time we are so well rehearsed and we've played the piece a dozen or more times - the conductor becomes something in our peripheral vision that just keeps us all in sync. Can a conductor conduct prerecorded music accurately? Of course not. He can come close, but only after practicing with that same piece over and over... believe me, I know... I took courses in orchestral conducting years ago and that was part of our training.
The key here is discipline. Practice. Listening. Being a musician and a sportsman. As far as drummers by nature not being musicians, I can't believe someone had the sightlessness to even suggest that! It's been said that the most difficult instrument to play is the simple triangle; it is so transparent and must be absolutely perfectly timed..
As a classically trained musician, what I can say is that the two types of musicianship are very different. I have to do things in rock 'n' roll that I never would have done in a symphonic setting, and vice versa.
With this in mind, might I suggest a pulsing light or the visible metronome? Visible in the periphery this would probably come closest to a conductor. But not just off-on ; it would have to be a ramp effect - triangular or sinusoidal brightness response. Think of it this way - a conductor is an analog stimulus - a click is a digital stimulus. We can sense rate of change between beats thru a conductor - you can't with a click.