It would be great if the conditions of the fairways and rough could be adjusted, similar to how green speeds can be changed. I don't think it would be very difficult to program, and it would add tons of variety to the game....
In real life, depending on the weather and how the superintendent has set it up, a course can be relatively hard and fast, where the ball bounces and rolls a long way and the fairways can be hard to hold --- or soft and slow, where the ball stops in the fairway a long way back but the greens are "receptive" and easier to hold with long irons.
On WGT we could have firm, standard and soft. (to simulate harder or softer greens, we could slow down or speed up the greens with the existing variables)
Similarly, rough can be cut or allowed to grow ... it seems like it would be fairly easy to allow users to choose between heavy, standard or light. With "heavy" or thick rough, 20/25 lies could become 25/30, and 30/40 could become 40/50. Light rough, obviously, would be the opposite: 40/50, for example, could be eliminated and 30/40 would be the max.
Again, I don't think it would be hard to do... all variations in the rough would stay the same; it would just be relatively thicker or lighter compared to normal. Along with the existing wind and green speed options, these adjustments would allow WGT and players to radically change playing conditions, adding a lot of variety to the existing courses.