There are a lot of plot differences that we don't know if they will carry through. For example, there is no Daphne or Monica in old WiaB, We don't find out about William having been in prison until much later, there's a much more intense vibe to the stalker girl Donna, which leads to the main plot difference. I'm trying not to spoil things, because the story might follow the same path, but the details will give it weight and consequence. Knowing what was already there means we get impatient, waiting for certain scenes, and Ocean might change them because he wants them to still be surprising.
There are a lot of connections and backstory to be learned ...but I would only consider it if you're really really curious. The new characters are much more believeable - Old WiaB Katie is angry at William, then he says something and all the years of anger go in an instant. Now, she is suspicious when you try to fix things.
The old WiaB had some great directions for the story, and was so different from other AVN's when it came out - but I'd suggest it's better not to get the stories mixed up. In some ways I'd rather forget what was there and just know the current story. Same with Ocean's change to the relationships that will come in chapter 4 - the main reason it's a problem is because I am used to thinking of the relationships as being X but know they're Y.