I'm far from an expert at one Pocket. I have watched quite a lot of accu-stats tapes, and I've played a little bit. First With my friends (we all knew nothing apart from what the tapes had taught) then later with a truely expert player. This is my list of why I don't think playing one Pocket exclusively is a good way to get bettter at all games:
1. One Pocket banks. One Pocket banks are often lag banks. Lag banks are bad in pretty much any other game. You're risking roll off and bad contacts and they're hard to judge. ESPECIALLY 2 or 3 rails. You are approaching the Pocket diagonally, and are almost certain to leave it on (for the Pocket you are shooting at). That's pretty bad news if you're not playing one Pocket.
Then you have the extreme spin transfer banks. These are somewhat rarely used, but still viable for other games. I think most players can go a month without using any banks like that in other games, especially for the corners, which is what is used in one Pocket. I use them somewhat more often in the side Pockets, they offer bigger targets and usually give more opportunities to be used. But one Pocket is not about the sides.
2. Take out shots. These are completely useless in all other Pocket billiards games.
3. Bunt safeties. These are the standard safes where you bunt an opponents ball, laying on the short rail next to a Pocket, to the long rail next to the Pocket, leaving the cueball frozen to the short rail. Used as a kick as well as a bank. Vital for one Pocket, completely useless for all other games. There are also shots quite like this in other areas which are equally useless.
4. Tightly played short side shape. This a good skill, which one Pocket teaches well, also found in straight pool and 8 ball.
5. Reading the stack. Straight pool teaches this equally well. One Pocket has maybe more "Wild" and creative stack shots, because you are rewarded for near misses (creates threats). So I Guess maybe you'd learn a trick or two you could use in Straight pool if you're a fast and loose style player.
6. Moving (leaving balls near Your Pocket to create a threat, or moving oppents ball into non-threatening positions). Not useful in other games, except maybe 8 ball. The UK 8 ball games have a lot of this, because of congestion on the small table and tight Pockets but the way you do it is a lot different than in one pocket. In UK 8 ball it Works because balls on the rails are considered safe. It's really tough to shoot one in when it's on the rail on those tables. If you do this on a US table the shot as actually easier for Your opponent in many cases.I suppose you could combine them With a safety and use them in straight pool maybe. Personally I think it's too complicated for that purpose.
7. Side Pocket shots. One Pocket has none. Good to know in other games, wouldn't you agree? OK, OK I SUPPOSE you could shoot one in the side to spot it, not much used, not really emphasized.
These are some bread and butter shots in one Pocket and one not taught at all. Of course you shoot regular shots as well, but I don't think anyone would seriously suggest that one pocket is the best teacher of open table play?
