Yeah but your grievances are with the broken gameplay mechanics, not the weapon itself haha. I know for a fact, that it would be great in a balanced game with well-designed combat. Imagine the Aquila, with actual damage (cause it's made out of fluff right now) in a game with aggressive enemies and no color coding.
... Have you seen the range on just its normal attack swings? If you bump up the damage to where it's slightly competitive with Rebellion, then Rebellion becomes completely useless because it'd outrange Rebellion in general, does relatively sound single target and absurd AOE damage in comparison and covers a MUUUUUUCH larger range that sort of ends up going against the melee design philosophy that DMC games have. It's just a hair shy of the range the Blades of Chaos have where its hitboxes are concerned for crying out loud.
Even the Lucifer which is the closest parallel to the Aquila had the good sense to give Dante complete frontal 180* coverage on his spinning swipes but only within a very narrow range while Rebellion had less horizontal coverage (With exception of Combo II) but more damage and more reach to compensate. Very useful for Legendary Dark Knight.
It wouldn't be overpowered against Rising Cyborgs for example just like L'Etranger isn't. Same general idea (crowd control weapon, without overpowered stun-locking) but with a different focus.
L'Etranger doesn't pull in enemies on the far side of the screen regardless of Raiden or the enemy's position and deposits them hit-stunned right next to him. The Buy-In mechanic is what defines the weapon and what essentially breaks it.
Besides, I rather they keep moving forward with weapons - It's bad enough every DMC game worth a damn has Gauntlets, Swords and a few guns that don't change too significantly across each iteration, we don't need them to keep trying to shoehorn Aquila into their game design.