JES
Now you are asking me to come up with a creative idea, rather than just reacting to something already in the ground. I am clearly better at the latter.
I do understand your underlying point because when you start to try to think of specific examples, there just aren't many. This is mainly due to the fact that so few courses have wide fairways in the first place (which may be your other point). The few examples I can think of often need narrowing because of some other design flaw or because of technology, where the intended hazards have become obsolete. I generally do not like the idea of new rough, but I do think some holes could use some narrowing through good bunkering. So, here goes
1) Charlotte CC #15 - This is a slight dogled left with several bunkers on the outside of the dogleg. From there it goes downhill to the green. Ron Prichard is restoring the course and has added a cross bunker on the left and several additional bunkers on the left up closer to the green. This effectively narrows the fairway in several spots, but I think it is a good change. As players hit it farther, the bunkers on the right had become less and less relevant and lots of players could just bash it over the corner and down the hill toward the green. The new bunkers and narrower landing area will at least force players to think about what they are doing before they rear back and kill it.
2) Valhalla #6 - I liked this hole better before they changed it, as they have now moved the green back 150 yards beyond the ravine. Still, with that change, I think the fairway on the far side of the ravine should be narrower. It is just a big wide runway up to the front edge so that a player who hits it out of position can really just hit it anywhere across the creek and then pitch on. I think it would be more interesting if there were a bunker on one side of that landing area, narrowing the fairway short of the green. Then, a player who lays back too far or hits it out of position would have to make some decisions about what to do next.
3) AGNC #18 - I would prefer it if they had just left Augusta alone and had no rough anywhere. Despite that general view, if you look at #18 in a vacuum, I can see why a narrower fairway with rough on the left makes sense. I think it had gotten sort of silly when today's players could just hammer it well left and way beyond the bunker. Angle of attack does not matter much if you have a wedge from a perfect lie. Forcing the player to go either short of or right of that bunker makes it a tougher decision and helps bring the bunker back into play. Maybe that problem was fixed by the new back tee, but I can see why a narrower fairway there improves the hole.
I admit that I am agreeing with a prior narrowing more than I am advocating any new changes, but such are the limits of my creativity. I am also prepared for whatever onslaught of outrage is spawned by that last one.
Art