Chris,
I suspect you're right. The sand at Commonwealth didn't look as if it's been subject to those machines. I've recently seen them around my home course - they used them to churn up the sand where it had compacted in some of the bunkers. Problem is that it churned up the base. When we got the recent rains the silt all washed up and then the sand/silt mix packed down and we got black mush (which goes hard as soon as it dries out) - which then means they'll bring out the machines again and the problem gets progressively worse. The other thing those things do is ruin the edges of the bunker where they drive in.
David,
Good to see some input on the 10th at the Valley. It's a good hole. I didn't mean to give the impression that it wasn't. This thread started out talking about good lost holes. The old tenth was a good hole which has been lost, but the new one is a good replacement (unlike many examples on the sandbelt when a good hole has been replaced by a mediocre one). Having said that, a lot of the members don't like it. I don't know whether this is a reaction to change (and having lost one of their favourites) or whether they find it more difficult. I can't see how it's more difficult for the majority who find the front two traps - the recovery from any of the traps on the old hole were just as challenging. The back traps, however, are a challenge to the less-skilled bunker players. I would be interested to know Mike's view on the front right trap re it's narrowness and high back.
I don't think your suggested tee placement for 5/16 would work. A shared tee area, maybe, but I don't think having one hole playing across the line of another should be encouraged. The old tees were almost side by side. Now the new 16th tee occupies a spot where the old 5th teeing ground was, but about 15m forward of the medal tee. Even though it wouldn't be ideal. I've wondered if you could solve some of the 5th's problems by moving the tee, say 3-5m right and 1m lower, thereby partially restoring the original design. I don't think it would impact terribly on the speed of play as, at present, players on one tee usually wait for the others to play. I suspect, however, that if they ever make changes it'll be at the green end. As the hole currently plays, the green sits a bit awkward to the line of play. Also, the right bunker has become more of a rear bunker. When the pin is right it's upon on a ridge when there is very little spot to land the ball. The biggest problem from a short term point of view, though, is the quality of the putting surface.