I've been hanging out at Dave Nethery's blog a lot lately. You should check it out, too. Something that impressed me recently was the sihouette value of these simple poses. They aren't action poses with lots of obvious negative/positive space. Just simple portraits (like the Chessie Kitten should have been).
I have taken the liberty of blacking in a couple of Dave's drawings to prove my point. I'm sure you will agree that they are perfectly readable without any interior detail.
Now go over to Dave's blog and search out the original works to see how your imagination matched up with his intentions.
Oh, and check out the Rune Bennicke sketches he just posted. Wow!