Since he’s up-front that he’s gonna be including opinion, and about his own limitations when it comes to presenting certain philosophies (IIRC for Bergson he was like “look I can’t figure out a way to explain this that doesn’t seem like total bullshit, but I’ll try”) I don’t really get the complaints about the book. I think it’s great. Why would you want Bertrand Russell to write such a book and not provide his analyses? It’s better that way! There are plenty of similar works by people mainly known for writing their histories of philosophy. Go for those if you want a just-the-facts version.
Agreed. I'm much more comfortable with "this is my take on this subject, and here's how I'm a bit biased, but I'll try anyway to be as objective as I can as well" than "this is the way things are"-style proclamations.
Wasn't it based on lectures?