I have thought about this alot, and my take on it is as usual, in poker as in law, it can go either way and/or both ways. Playing short handed helps alot in ring situations when you find yourself heads up against a player that plays nothing but ring, and you suspect he has a hand that you can get him off with a well timed CR, or by capping the flop and making him think his TP/GK is no good, or something like that. In full ring, you will see people laying down hands alot more than in short handed- its not all that often a mizor in a full game pays you off with bottom pair, although it certainly happens once innawhile.
But it goes both ways because if your used to short, you will often payoff in spots where laydowns are called for in full ring. Like middle pair with an ace kicker against a raiser, without a read, and that sorta crap- this is often a payoff hand in 6 max but not that good in full ring if someones bringin heat.
ALso, i have noticed that playing full helps the shorthanded game because it reminds ya that poker is not a circus where you can raise with any two and either mize the pot on a bluff or a draw, or get there enough times for it to be +EV to raise with 78s in MP every single time you get it. When my SH starts to open up too much and i feel like i am playing too mizorly, i play some full ring to help with patience and discipline, which is easy to get short on when your in a short handed frenzt playing 3-4 tables of 4-6 players.
Bottom line is you need to be able to play both to be a well rounded player with an understanding of the game.
Man i dunno why im in the mood to post all of a sudden. I still hate poker though, so dont anyone go thinkin any different!