There's no polite way of telling you this lad, but you're talking out your ass. Good stories stem from great characters; it's for that same reason why entertainment media studios will often take characters from other intellectual properties and carve out their own story built on their assets and personalities.
The main story continuation would have been a far superior update to receive following this Gomira update because it's focus on Madeline would have driven the plot further and added different dimensions to it because of Madeline's relationship with characters like Serena and Lana, the latter of which, as we're all now aware is a fiercely compelling character which resulted in an strong story in the last main story update.
Even if you went with a character like Gretta, there is evidently an interesting and likely very satisfying story to tell because she is Waldo's wife. And Waldo, in my experience, has been one of the most resentful minor antagonists in 2D porn games that I have played, and I know for sure that a many other players would agree with that sentiment. So, the build up and thrill of giving Waldo his comeuppance in slowly taking his wife away from him after failing to appreciate her, would have made for an interesting story, and that all comes from what has been established from Gretta's character.
With Holly though, what story is there to tell? I mean, she's engaged to MC, the battle for her hand in marriage was won in the main story, so all that's left to tell now is a drawn out story of how they do or don't get married, and how Holly will eventually warm up to MC and learn to be more sensitive towards him. And that's just disappointing compared to the world-building story arc which would have been offered through Madeline, or the satisfying story arc which was available in Gretta.
I hope that clears things up for you and your simple mind. Have a good one