Look, rules are made to be broken. My best pots came from wonky, lopsided clay. Perfect symmetry feels dead, like factory stuff. Let the material breathe a little.
Totally, I get where you're coming from. Forcing everyone to make the same perfect shape just kills what makes handmade stuff special. My old teacher used to drill symmetry so hard it made my work feel stiff and boring. The basics are good to learn, but they shouldn't be a cage. Letting the piece have its own character is the whole point.