with your first post, I think the upper body is just a little stiff, with the hands in the pockets I would expect the character to be a little more slouchy.
If you were trying to give it a bit of motion you could squeeze in a little secondary action- where the torso would come down or forward a little after the foot plant. But for a simple walk cycle stuff like that isn't really nessecary- I find watching live action walks that a lot less moves then I imagine in my brain- walks are pretty simple in real life.
I think the hardest thing about walk cycles is you really want it to look spectacular- but they're actually very strait forward. There's always that nagging voice in your mind saying - it needs to be more *insert adjective here* Best to think simply.
In the second one I can only see one little blip with the under arms right at the end (our left not the characters) where the negative space grows and shrinks a little awkward- I think it's a single frame that grows when it should shring or vice-versa.
The idea is really neat- and your clean up is very uniform. My clean up looks like I drink massive amounts of coffee... and I mean I do drink too much coffee, but still >.<