I think my biggest gripe is the characters made some poor decisions, even though they were crucial to the story. I wasn't quite sure why Ursus waited for Gwynplaine to come out of prison when he went into prison so why would he come out an hour later? I don't know. The writing I guess needed some tightening. It works overall even with some nit picks.
Great point. I myself, right or wrong, do tend to be more forgiving... VERY forgiving with the writing and plot when it comes to silent films, just because the medium of film was so new and it wasn't really until some great filmmakers burst onto the scene in the 1930s with early "talkies" such as Ernst Lubitsch, Howard Hawks, Frank Capra and so on that dialogue, continuity, plot elements, etc took focus in using film as a medium of storytelling.
But that's just it. With the silent films, I can easily forgive "poor writing" or elements in the story that maybe aren't explained well or don't match up quite right with continuity or lack of explanation for what's happening on screen because first and foremost in silent films I'm looking at images, atmosphere, tone/mood, and a consistency in overall theme and the story at a macro 10,000 foot in the air view as opposed to the granular minutia. A truly great silent film that I watched for the first time last year, and to be honest, one I had never heard of is called Seventh Heaven. There's some plot inconsistencies in that too, but it's a great A+ film for me. The same thing with some of the other great silent pictures such as Greed, The Cabinet of Dr. Caligari, and Sunrise.
If I can get behind the characters, tell them apart, marginally understand what's happening in the story, even if I can't explain every single scene or how and why we got there, I'm perfectly OK with that. Silent film is about emotion, tone, and being absorbed into an entirely unique and otherworldly realm of storytelling. And it's great.
Here's a very rough copy of Seventh Heaven that someone uploaded on youtube. The version I saw was much clearer: