To be honest. I'm still waiting to see why Eric is needed at all. Was Eric the reason why Max start using the lessons with Lisa to see her naked? not really. Was he needed for most of the "opportunities" that are already in the game? not really. Will he be needed for Max to get sex with Kira when she is finally in the game? not really.
The only thing for what I can see Eric as needed in the game, is to show us that Ann isn't really a bright person, and that she is easy as fuck. Bringing her new boyfriend to your home when you actually don't know him that well, having him giving orders to your family, having him giving an ultimatum to her kid while she doesn't see or care about anything but fucking Eric all over the place while her kids are still home, all this shows Ann isn't very bright or smart tbh. That's the only thing I can see Eric being useful for right now. Otherwise he isn't needed for Max to keep scaling things with his family. It will become more aparent when Kira is in game, because if Max was still strugling to scale things with his family, aunt Kira should help him, again, without Eric being needed so...Still waiting to see the "Eric is needed for Max to do things", that the dev said.
Eric isn't needed, but it's the easy way. It also brings in the NTR, since the mom is a future LI and she wasn't with Eric since the introduction but instead she gets with Eric after the game started, it is a NTR situation. Then the game becomes, grind money to challenge Eric, get to see afew nipples while Eric is fucking girls and later on, challenge him and maybe win. But to that you will have to grind a lot, and then when you finally get rid of Eric, you will have to keep grinding for a few versions before you can have sex with the family (excluding Kira).
But well I don't really see the "dev of this game of 'his'" being really worried about anything we say, as long as there are people paying him to see "another story" he doesn't really care. He is getting money doing the same game, in ren'py with few original events/dialogues/opportunities and adding animations that many people won't see because it involves Eric and Ann. But well if people would pay for that, to each their own, I won't pay shit to see the same game but worse, because at least in the original BB I can mod it to get rid of Eric but here I can't even cheat money without breaking the game, or using old saves, even if the dev said the save problems will be fixed in the next version, who will believe him when he promissed another story and the option to avoid NTR and Eric but then said he is needed.