The game should have let you choose your girl.

Also, it could also be an interesting R=U Theory.
The real story goes along and Squall never actually fell in love with Rinoa, so she got sealed for many generations 'like Adel'.

So, either she gets mad, takes Seifer as her mate and wants to destroy the world,
or she's just bluffing so that she 'Rinoa the past.. or present, depends on how you look at it' gets to have Squall as her mate.

How else do you explain Squall being so rude to Quistis?
Or that Quistis felt it was a misunderstood love?

That Squall is repulsif and heartless?
Although we all know that was Just a cover up of his true identity.
Still... a girl like Quistis and his heart wasn't already taken?
Makes Absolutely no sence at all since he's not gay, may it be H-S or joyous. (Only time he has a smile is at the end of the game)

And what about Quistis?
She looked as Squall as her brother?
Talk about serious insest/amnesia.
Did she loved him or not?
or
Would she sleep with her brother?
No and No