I disagree. The simple fact that Ian is once again open to try a relationship with Allison, or Holly, or Cindy, Or Lena or even Minerva seems to me enough indication that he is growing past whatever happened between him and Gillian in the past. Unless Gillian is back to become another possible romantic route i still see her presence as just more drama for drama's sake. And even if this were to be the reason for Gillian to be back it would still take time away from the already quite big cast the game have for both protagonists.
Anyway, can't comment much about Stan since i haven't bothered with his route other than using the mod to check the gallery.