this message may be offensive
I've been thinking about the seven lately, and I've come to the realization that Piper is the only one that isn't irreplaceable. The others have some destiny to do, or some special powers, or a curse or they were chosen for something. But Piper? She just has charm speak, something Drew also has.
The solution I've come up with? Split Aphrodite into her three main epithets like her worshipers did.
Aphrodite Urania, the motherless child of Uranus, is the caring mother aspect of Aphrodite. She's also goddess of the more 'pure' aspects of love, like love for family, friends, people, and innocent romantic love.
Aphrodite Pandemos is a child of Zues, and is as fickle as the wind. She's the more painful and confusing aspects of love, as well as the more carnal, sexual loves. She puts people together, and breaks them up just as fast.
Aphrodite Areia is the warlike Aphrodite. She's spartan in nature and puts her place firmly on the battlefield. I hope you can tell by this point who I'm putting with who.
Now that the introductions are over, here's how I would make Piper special compared to other children of Aphrodite. And it starts with Selina.
Selina is a daughter of Urania, which is seen by how she cares for the people around her. Drew is a child of Pandemos, as she breaks people up the second the relationship she put together gets boring. But a child of Areia hasn't been seen in centuries. Until, of course, Piper McLean.
Boom, now she's irreplaceable. Drew ain't got shit on her now.