I personally like the quick faces far more than the poses. Accurately capturing faces is one of the most difficult things for me and I think you've done a decent job.
I don't think your brush lines look messy per se, but to me the poses do seem a little stiff. Granted, the poses you've done may all be stationary so that's probably a big part of it.
I think you're on the right path and my suggestion is to just keep pushing forward; focus on capturing the basic essence of each pose or expression and then build upon that.
It looks to me that your on the right track and moving forward pretty well. Your lines seem pretty fluid in my oppinon,especialy the two minute gestures. At the very least you've captured the essence of each pose and I love the fact that your body types appear to vary. Keep going. I look forward to seeing some longer, more detailed studies as well.
