Schrobby said: Especially compared with Sakuya who's time keeps running whenever she stops it for everyone else...
Actually, Sakuya doesn't seem to age that way, given her dialog that sounds very fond of her life. Like, she says she won't commit suicide since that's a waste, she always wants to treasure her present moment, etc. I should think she doesn't age while in her World. And what with the possibility that she's a lunarian.
...Or Sakuya simply isn't aware of her time running faster.