Just to expand on what every body’s been saying here, I think the thing about the hatching and the detail not really pulling it’s weight has to do with not looking at the composition as a whole, but kind of more as a series of objects. Cut any one character or object out and have it stand on it’s own in a sketchbook, it’d probably look pretty good sitting there. Wouldn’t need to change the level of complexity at all. 

But putting everything together into a composition means making some tough decisions about what’s most important and why, so the viewer’s eye is drawn to where it needs to go in order to read what’s going on as soon as possible (like Toji was saying, establishing a hierarchy of detail.) 

So looking at the latest picture there, most of the characters are given equal amounts of detail, and roughly the same level of tone- if I walk to the other end of my room and look at it, most of it kinda blurs into a single grey tone. I assume the character in the bottom center is supposed to be the main character, but I only know that because I’ve seen the previous pages- standing on it’s own, he’s not the guy my eye goes to first- I’m more drawn to large black areas of various character’s hair, because they contrast with the large areas of finicky detail present everywhere else. This probably isn’t what you’re going for, so at this point (or really, on your next picture), you’ve got to take a couple steps back and question why that’s happening, and how you can change it. 

Here’s a quick couple of things to think about playing with when you’re sketching out a composition, and kind of showing where your head should be at in the initial lay-in stage. If I took these characters as a simple series of individual objects just copy pasted next to each other, it’d look like the first picture- pretty flat. But engaging them at a more abstract level- treating them as a whole- with a handful of pretty simple concepts I can really get a lot more out of them. 
(Ignore the style- I know it’s not close to what yours is, but the principles here apply regardless of style.) 

Before launching straight into your next drawing, try thumbnailing out a couple ideas first so you can work out what your priorities are going to be as you go on to the finished drawing. A good example of thumbnailing would be something like this: 
http://deadoftheday.blogspot.com/2010/07/perspiration-composition.html 
You can see that even though Bama is dealing with a TON of detail, it all stays readable and coherent- even reduced to a teeny tiny size- because he picked out where his areas of highest contrast and detail were going to be before going in and painting it. 

So if you were to do another group shot like this again, you might start off with trying to figure out how to make that main character stand out- you could throw a shadow off him of the other characters to make some contrast, you could set him against people with darker clothing, you could give him a stronger light source with more large, distinct areas of black and white than the rest of the characters, you could make him more detailed and make everyone else less detailed, etc, etc. There’s no one solution there, it’s putting some significant thought into these issues that’s the important bit. 

If nothing else , every 10 minutes or so just take a walk across your room and look back at it and gauge how readable it is from that distance. If you can follow what’s going on with it from 20 feet away, it’s probably a solid composition. If it’s unclear, it’s time to start doing some thinking on why that is. 

More amazing advice from Kevin O’Neill

See it in context: 

http://forums.penny-arcade.com/discussion/comment/24989874/#Comment_24989874