I think in the first half of what you said, you articulated well why the players didn't like Jill. My honest answer is also that this character doesn't fit in this type of game as a main LI.
However, I hope I misunderstood you when you wrote that Jill was superior to Sage in the previous episode. Again my opinion, Jill has never been better than Sage or any other LI in any episode. I'm right in that in the last episode he made a big leap forward compared to his previous character, but he's still not the first. And why are you surprised that DIK MC doesn't fit CHICK Jill? These two characters with such options are Fire and Water. What modest virgin girl wants an idiot boyfriend? I hope my comment wasn't offensive, I didn't mean it to be.
(Sorry for my English, not my native language)