In some books they are more casual about mentioning injuries than others. Especially the injuries of others who aren't narrating. I remember reading a few times something along the lines of, 'oh, Jake was minus an ear and a leg, and someone had gutted Marco'. Earlier in the series stuff like that would have gotten more description. But I guess the Ani's....got used to getting their limbs hacked off?
It may have been ghostwriter's preference - some people may not want to go into depth describing gore. Still, losing limbs loses it's glory when a quick 45 second demorph will fix it right up. I remember a scene from one of the books, I can't remember which number, Rachel beats a Hork-Bajir to death with her own severed arm.
Still, anything not immediately lethal can be almost completely disregarded - if it won't kill you within two hours, you've got bigger things to worry about. Losing an ear or an eye sucks, but you can still fight until you can demorph. Being gored or losing a limb is the only real way to create stress; trying to escape a fight to demorph creates tension in what would otherwise be an almost monotonous fight. Still, after it becomes almost as a habit, the anxiety created by it will eventually decay, and this will likely also show in the author's writing.
Also, while depressing, it may have been as simple as a publisher saying that describing internal organs isn't what they want in their books.
Back to topic, I have noticed that Marco was definitely the most injured towards the beginning, but as the books progressed, it seemed as if it was about even for everyone. Each character somewhere along the line had a defining moment, given in different books. If everyone was gutted in every book, it would get very boring very quickly.
