I understand the frustrations of missing positionals in fights, but if I miss one, I can usually see why and anticipate the position I need to be in within the GCD to fire it off correctly. I think the only mob that moves around that much for me to miss more than one positional are the Spinner-Rooks of T4 (tanks dodging pox), but you can land one when they stop for spells. Most mobs stop at some point to attack/spell/skill and you can catch them that way.
