[DEV Question] Why is this allowed?

[JunseiKei]

And I still think that your potential with an i110 head, hands, waist and feet and other gear i270 including the weapon should not be miles above having an i110 weapon and all other gear i270.

Yet, I'm still convinced that, if you join a party with someone having a really low body piece, you wouldn't even notice, since the DPS would be fairly acceptable for the fight. Especially on A9 which is pretty low on party-wide damage.

You would notice when the DPS use Blood for Blood and get one shot since body gear also dictates how much HP you have as well as your defensive stats. Maybe not on A9, unless Faust cleaved them, which would probably be more on the OT facing it the wrong way. Probably. However, 10, 11 and 12 get target specific mechanics that would kill them off, especially if it's more than one piece of gear. The harder pieces to notice would be accessories; they don't provide HP nor any real amount of defense.

The weapon will always be miles ahead of the others since, as I've said, it's what SE decided to use as a stat capper. Even if it were another piece, say an accessory, if it somehow decided where the stats would start meeting soft and hard caps, that would be the most important thing to upgrade. The weapon is really the only real hard cap I see (though I could debate critical RATE and just RATE being more toward hard capped than soft). Everything else has a lot of soft capping (AKA diminishing returns).