I will do my best to review the miniseries and not Ron Jeremy himself or his victims.
To start off I'm not sure what viewers were complaining about. The early part of the first episode DOES explain how he entered the porn community and how he rose to fame. Not in much detail, I think they were hoping two short episodes would explain the basics in case there's anyone out there who doesn't know anything about Ron Jeremy. The documentary also goes into detail of how most of these actors first met and worked together. They tell some fun and silly stories about Ron before getting into stories of how he would stock, molest, violate, and rape women. Almost all are first hand accounts. They don't allow the witnesses to tell too many stories about other women. My main complaint is while we get plenty of interviews with his coworkers we do not get much in the way of actual investigation, nor do they interview any family members or law enforcement officers involved with his case. We do however get many accounts from the victims of how they were treated by society after coming out and sharing their rape allegations publically. We also don't see more than a few frames of the trial and nothing about his arrest or the official investigation. Its the kind of documentary where the film makers just let the interviewees talk and that's it. They don't have any voiceover explaining facts, and only a handful of title cards with information. For this reason I have to rate it low as a documentary, but the interviews were illuminating and felt genuine.
Also as opposed to the majority of American documentaries, this one does an amazing job of not pushing you to believe a viewpoint or get the viewer to feel a particular emotional state, or take a position. Nor do they speculate on any facts. I like that and I wish more documentaries took this approach. I'd also like them to have more facts. All they documented was a bunch of verbal stories from victims and a few from his coworkers, like cameramen and directors. The second episode ends with his legal situation up in the air. I wonder if now was the best time to make and release a documentary like this. Maybe they will do a follow up. No official word. I would have liked something much more thorough.