I was never sure how that helped - a vague pointing towards the front of the plane, the wings and the back? Where else are the exits going to be?

Much more useful was to add into safety briefings a reminder that the most usable exit could be behind you. Sounds simple but most people are used to going forward when they leave a plane.

I think it would be valuable to have a small plan of the plane at each seat showing exactly where that seat is in relation to each exit.

Oops, gone a bit OT...