Dude is a serious greedlord and liar unfortunately.
There's a reason why I always made the joke that Alice was a self insertion of DS since she always needed money.
I never played the "original BB" so i'm lost.. what Eric does that everyone hates him
Badly explained game mechanics, mostly (or rather people not getting them).
So, Eric is your mom's new boyfriend and he makes it clear from the start he wants to bang every woman in your family (which you do to). Problem is, while he's an obvious alpha with the matching arrogant attitude, charm and success, you're a wimpy know-it-all who's in way over his head and no one in your family thinks too highly of you. While in most cases this would make an interesting scenario, people saw him as an impossible boss.
Now the game mechanics that made it seem he was overpowered. He actually used the same ones as you. You spend time with your sisters, doing things for them, your influence goes up. He spends time with them, and his influence goes up, cancelling yours (or yours cancelling his, whatever). In most cases this wasn't even that relevant, since he only spend time with Alice, once or twice a week. Every week, though, he'd go take the ladies shopping, earning him a major boost (which again, you could cancel out during the week with a simple grind because there wasn't anything else to do anyway). Ann got the most of his influence, but doing your chores kept that influence on a minimum.
But the final straw was that Eric was indeed impossible to beat. No matter what you did, or what dirt you found out about him, or high your influence was, Eric could do no wrong. You caught him peeping on Alice with photographic evidence, and still no one believed you, or dismissed it. This basically made his influence a non-factor (then again, a lot of the game mechanics were essentially non-factors). Eric was just written poorly