Ross:
My take on the ground game and it's relevance to GCA has always come down to one core issue: variety.
If a player has multiple options from tee to green, and on the green, then the game is more exciting and the margin for error arguably increases since the possible methods of execution and corresponding failure increase. If you're only shot to a particular green is a forced carry you either carry it or you don't, but if you can bump and run a shot or carry a shot you've got two possible shots and two possible ways to screw it up. It also greatly enhances the rub of the green, which is a variable that makes the game very exciting, although less predictable which is why the PGA Tour doesn't prefer it.
In comparison, if the line of play is dictated to the player off of every tee, I think the player will become resentful of his lack of choice, and, in fact, bored with no option other than hit it straight, avoiding the trees and/or bunkers that define the boundary of play. The same thing applies to approach shots . . . if I've got a forced carry into 18 greens and the approach is either up or in a bunker or other form of hazard, I'd say that will become boring, and also single dimensioned. It will test my ability to control distance and trajectory but it will not test my imagination or ability to recover.
It also takes out the risk reward element which should be ubiquitous in first rate design, IMO. For instance, perhaps a forced carry over a menacing bunker is required to get within 10 feet of a particular pin but a bump and run can be played to get the player within 30 feet, totally avoiding the bunker and the line it is on. Multiply that type of choice over 18 holes and you're giving the player more ways to enjoy the game, more shots to attempt to hit, and also, btw, more things to think about which may cause some indecision and lead to more unforced errors.