Actually, I think that at some point, some like this will happen. DPC is giving a lot of chances to the player to incorporate to Sage's route later in the game, and I think it's because Sage is the one that actually is going to need MC the more in the future. I don't think Jill is going to have a big conflict in the future, probably Bella is going to be better without MC if her husband returns, Lily and Nicole can help themselves and Maya and Josy... I don't actually care, but I suppose they will be OK with Jill's help at some point.
But, after being fooled by Chad, Sage is going to discover before leaving B&R that most of her "sisters" have been lying to help and making a whorehouse and a drughouse from the sorority she's the president, and the worst of all, his father is going to be involved in that and her family is going to fall apart. She's going to be really alone, she's going to think that the entire world is against her, and is going to need someone to really trust to not get crazy.
I suppose that when the ring of drugs and prostitution of Quinn comes to light, MC is going to need to choose between being at Sage's or Quinn's side. But probably DPC is going to make the MC to involucre himself in Quinn's business more and more in the future if he's in Quinn's route, and there will be a no-return point in which MC will be too involved to leave Quinn and help Sage.