because if you're smart about it you position yourself in a way that only one can hit you, that comes down to dueling positioning also.
How do you even arrive at such a conclusion? In a duel, there is only ever one person that can hit you. You learn nothing about positioning against multiple opponents from dueling. Basic footwork from duels would translate, but if you move in a group fight like you move in a duel you're going to die against competent players.
Anyway, most advanced concepts don't translate directly from duel to battle. They are present in both, but have different applications.
Timing in dueling and timing in group fights are different in scope. In a duel, timing is important for disrupting rhythm of your opponent and mind-games. In a group fight, you shouldn't be focusing a single opponent to the point where this is a serious consideration. Timing in a group fight is more about switching targets and doubling-up on opponents with a teammate.
Feinting skills can translate, but feinting too much in a group fight leaves you open to attacks from other players and doesn't put significant pressure on someone with a shield. It doesn't matter which direction you're coming from if I've got a shield that blocks them all. Like you said, group fights will teach you when to turtle. I turtle against feinters, because my teammates will catch them off-guard.
Chambers in group fights are much riskier than in duels. You're taking a risk by attacking into an attack, which is mitigated by personal skill of course but which is a risk none the less. If your timing is off, you can get hit. In a duel, being hit once isn't always a death sentence. You'll recover fast enough to block a second attack. In a group fight, you may get hit a second time while you're being staggered from the first blow. It's a matter of risk assessment. If you think you can handle it that's fine, but you always run a greater risk in a group fight. You don't learn that change in risk from a duel. Kicks are the same way. They immobilize you, opening you up to attacks. That isn't to say you shouldn't use them in a group fight, because you can if you're aware of the positions of enemies. If nobody is in a place where they can flank you quickly then it's safer to try a kick.
That plays into positioning. You're right in that you want to place yourself in such a way that you can either block all incoming attacks with your shield or only be attacked by a single player at once. These are things you don't learn in a duel, because the focus of a duel is on one opponent. You're always looking at a single opponent, so you don't have to watch your back. In a group fight you have to be aware of the positions of your teammates and your opponents, and you have to know how to move to support your teammates while pressuring your opponents. That sometimes means moving in ways you wouldn't in a duel. You can always backpedal in a duel, but you can't always backpedal in a groupfight. A simple example for a simple concept.
Very basic fundamentals such as aim and manual blocking directly translate into everything. That's why they're fundamentals. Your anecdotal evidence about your personal experience in learning from dueling doesn't apply to all players. Some of us learned fundamentals in Battle, like me. Battle is where I learned to block and feint, and where I first applied distance control. I started developing advanced concepts in battle until the duel mode was released in the beta.
Also, it's Orion. Two O's, no A's.