Flying Weapon/Animate Weapon should be able to target the opponent's weapon. Targetting the opponents weapon would turn it into a creature for them, so it should have no use besides comboing with CC afterwards
This is a buff since it makes Animate Weapon strictly more versatile. But I don't think that it would really affect most Animate Weapon decks, as it's mostly a change which allows Animate Weapon to be used offensively as a form of weak PC when used with CC. The most worrisome case might be Eagle's Eye based Animate Weapon decks
Most flying weapon decks have plenty of weapons to cast on, so casting Animate Weapon on the opponent would leave one's hand holding a dead weapon card. On the other hand, it's common to have a couple weapons in a deck for drawing power. Usually it isn't worth putting an Animate Weapon in the deck, which is probably going to weaken the drawing power since it's mostly useless unless near the second copy of the weapon. This would help make it worth including if the deck has enough CC
This buff's purpose is to open up more possibilities, not buff anything
Wrt Eagle's Eye, this is the list of one shottable weapons: Dagger/Dirk, Short/Long Sword, Short Bow, Discord
Random ideas: Aflatoxin deck might have a weird case of using this against a no creatures deck. Wings deck could web bows after animating