Within some recent threads, there were a couple questions/disputes on why wide fairways are a good thing.
While there are many good arguments both in aesthetical and startegic in nature, the engineer in me wants to distill it even further. After some thought, the conclusion I came up with is that you want wide fairways because you want, on average, consistent level of difficulty from tee to green.
What does that mean?
Let's say I can hit my 7 iron 150 yards and my driver 250 yards (I think that is pretty typical for a "decent" player). An average green size is about 5000 square feet (although the modern courses tend to be substantially larger), which means they are about 24 yards by 24 yards in dimensions.
From the middle of the fairway 150 yards away with my 7 iron, I have about +/- 4.6 degrees of room for error on my trajectory (left or right) and still hit the green. Obviously, there are many other factors like wind, shape of the shot, etc. but for this discussion I think this simple calculation will suffice.
If I transfer the same room for error (+/- 4.6 degrees) to the driver length of 250 yards, you get equivalent fairway width of 40 yards. That means that (at least for left/right accuracy) hitting a 40 yard wide fairway is about equally difficult as hitting a 7 iron into a 24 yard wide green. Once could argue that you have much more vertical (short long) room for errors with the driver since fairways tend to be much longer than greens, however, since the driver is much longer (magnifying small faults) and you swing at a much higher speed, I believe the difficulty level is still very similar.
What about putts? If a typical putt is from about 30 feet away, +/- 4.6 degrees means you can miss by up to about 2½ feet. Which seems very similar in difficulty with the 7 iron as you are expected to hit 2 putts, and 2½ feet putt should be quite makeable.
So, to me, wide fairways are not just a question about angles and strategy, it is about fairness and consistency. If you make the fairways too narrow, you are asking more out of driver accuracy than iron accuracy or putting accuracy. I prefer courses that test your skills in even fashion, and that means wider fairways. With bigger greens that are popular, the fairways should be easily 40 to 60 yards wide to offer equivalent challenge to the user.
It is all about the fairness.