Your potencies are already relatively high compared to what ranged can put out, and you have auto attacks on top of buffs that increase damage dealt (through raw damage, attack speed, or both(. The positionals at that point far eclipses what non-melees can already do.
Only DRG was truly hindered by this because their combo extensions and skill applications were entirely reliant on positional; if you missed the positional on heavy, impulse drive or chaos thrust, you didn't get anything except a 100 potency hit out of it.
Much less so in 3.x now because every job has gotten more abilities that deal damage regardless of positional (forbidden chakra, DwaD, etc etc)
