Living in Jerry Land (ARlington TX) and knowing he also has luxury boxes below field level there, makes me wonder if a simiar worms eye view could be incorporated in such seating?
There are some practical problems in buidling permanent structures - the gca would still have to consider the sun and air movement to keep the grass green and healthy all year round and these could cause problmes as much as trees around greens do. Most would want to be on the west side to keep viewers from looking into the sun, but that would depend on the routing, etc. It would just be one more big consideration in design, but it is one that should be considered for a primarily tournament course.
That said, I think we have all the tournament courses we need for now, don't we? It could be the first golf course renovation done by abuilding architect and engineer rather than gca!
And like TD says, there were builit in steps and so forth, which are gone, because they were trip hazards, I suppose. And, an even slope probably allows more spectators that parceling it up into seating, but I could be wrong.