I am surprised that someone hasn't whacked me for not recognizing the very obvious: Dickens' characters are vehicles for his social commentary, they are characterizations
! It's so obvious...maybe that's why it's not been mentioned.
In that vein it's hard for me to be so critical. I would say if Dickens' were writing now it would not be television scripts but Doonesbury-like comic strips.
Expanding on Hamlet's comment about the number of characters and given Dickens' penchant for lengthy and repeated descriptions, imagine the length of a novel with fully developed characters.
Forgot to mention how much the original illustrations by "Phiz" in the MR copy of BH so defly capture Dickens' various caricatures and much enhanced the reading experience for me.