An overwhelming majority of Patreons are against the idea of bringing back Eric and it's not hard to understand. His entrance in BB was practically the defining moment of that game. I personally hated how quickly he had every one under his thrall and the game overs I suffered as a new player left a bitter taste in my mouth. Especially frustrating was how every time it seemed like Max was able to get an upper hand over him, a brief conversation with a brainwashed Ann would reset everything back to the way it was or worse.
That being said, it was supremely satisfying to be finally rid of him, or at least keep him under control so that his influence doesn't completely ruin my experience. Teaming up with Alice to render Eric impotent and being able to see immediate results was particularly enjoyable.
If Eric were to be reimplemented, he would have to be slowly eased into the game. I feel what was lacking in the previous game was a sense of progress in the power dynamics between Eric and Max. For instance, showing Ann the photo of Eric peeping on Alice should decrease the amount of influence he has over her each week, while say getting caught peeping on Alice will have the opposite effect. Having bonus scenes and branching side quests that only occur when peeping on the girls, or catching Eric in the act would give players a risk vs reward incentive, while at the same time their actions could make the game progressively easier or harder over time.
Glamour doesn't necessarily need Eric reintroduced to pose a challenge to Max. I think a combination of Karen and Kate could fulfill the same role. Karen's influence is already felt early on with the implementation of punishments, while Kate has shown she can be quite manipulative when it suits her purposes. She's already very close with Alice and despite some obvious competition between her and Lisa, I can see Kate slowly pulling Lisa away from Max if he's not too careful.
As for Karen, she would become much more relevant to the story if Max starts attending the University. I can see her pitting Max against Kate and subverting the principal's agenda over time. Max would enjoy obvious benefits with this deal with the devil, much like Kate does with the principal, but with increased risks should he fail. After all, Alice attends the same school AND she's in bed with Kate. I would love to see how Karen exploits those facts to get Max in line, while Max schemes his way to decrease her influence.
Either way, Max needs some adversity in his life if his gameplay is to improve. As it is, there is no sense of agency in his playthrough other than how to get into the pants of every woman he meets. While that may be the ultimate goal, it is a very unsatisfying one if there are no obstacles to overcome.