When I chopped the first two chapters off of Karma, it wasn't enough. It still was too slow. I edited the bejeebers out of it, getting to the action ASAP. It wasn't until months later and a slew of non-responsive agents that I actually reread it with fresh eyes and realized I'd cut the soul out of the story.
One rejection said the story lacked balance. I didn't know what the agent meant until I read it again. Boom, there's action. It's hot, it's creepy... but it doesn't pull you into the story because there is no hint at who the characters are. It was painful to realize, but easier to fix than I'd hoped.
The question is should I resubmit? If the agents who gave me no responses read at all, it was only the first thirty pages. The rest of the book unfolded organically and, I'm happy to say, I'm still really proud of my work. They requested it int he first place, so they saw something in it. The lack of a "no thank you" isn't a de facto rejection, so it wouldn't necessarily be pushy or unprofessional of me to try again. Would it? I have no idea. I don't want to come across as too desperate -- but if the shoe fits...
Help me out, people. Your expert advice is appreciated.