New weapons aren't balanced by making mock fights against every other weapon but by seeing whether or not its particular strengths overcome the weaknesses inherent in its class. A gladius with a moderate slash, moderate length, and a wicked stab would still fall prey to longer weapons and be of poor use on horseback (as most 1h should be). What it would have would be a unique and specific capacity to penetrate tin cans, just like the 1h picks which don't have stab, and 1h spears, which have length but poor manipulability. It seems to me that even high Roman tier gear wouldn't be so overpowered that it would be unduly painful to balance. So long as new items are not aiming to be the absolute best (e.g. pre-patch side sword, pre-pre-patch Flamberg, etc.) balancing won't be a very difficult issue.
