Thomas,
I think your point generally follows. Even with a back to front slope of about 2 feet (which is about typical) ground level greens reduce, if not eliminate, the uphill flop shot required from behind the green. Lower greens tend to keep missed approach shots closer than when hitting banks on elevated greens. That wasn't always so - the old GBI courses with fw cuts around actually could carry missed shots well away from greens.
I always keep George Thomas' advice (to cross pollinate threads.....) that long par 4 holes ought to have "fair green" behind them, relatively level, because a shot over the green (presuming a back pin) is really a better shot than one coming up short, short left, or short right, and ought not to be punished as much. And, I generally design long holes greens as low as possible to the ground, because so many golfers will be running shots in and don't need a steep uphill approach area (even 7% or more will kill the roll of a typical senior approaching the green in typical conditions)
Side note, for a long time, I tended to give long approach shot greens more back to front slope, also figuring the average guy would need more help stopping a long shot. Then someone pointed out that a lower back to front slope would actually help them get the ball to back pins, so I don't do that any more. (From research, for average golfers, 1.33% or so back to front is enough to stop their lower velocity shots)
However, grade level greens can cause some problems. First, as always, is drainage, as its obviously easier to drain an elevated green. I have also found that the front approach - busy with golfers and several sets of mowers turning there - works better at 4% or more slope to avoid becoming soggy mess.
I also recall playing the Valley Course at TPC Jacksonville, in late afternoon. That course had ground level greens, and lots of pines casting long shadows, making it almost impossible to distinguish the green surface, which troubled me, and I believe troubles most golfers. I have found in my own work, that elevating the greens even a few feet tends to highlight them, even when shadows are present. Of course, the typical back to front slope is typical because it helps stop shots and allows the golfer to see the green surface, too.
So, is elevating a green slightly for those reasons not to be done to avoid the lob pitch from over the green? Especially considering that maybe 1-3% of golfers will actually be long on any given approach shot? I agree that a succession of lobs from over the green is annoying, but in reality, it would be nearly miraculous for any one golfer to face more than a few per round.