One thing that many VP/WP systems seem to neglect to address (including this one) are other factors that might decrease vitality. You would have to incorporate such things as swimming, running, and a host of other tiring activities, including combat, into VP loss.
Just finished the draft of v2.0. I finally got some actual input from a fellow DM over the weekend, and I think we came up with a much more interesting version, not to mention a little bit deadlier, but not by too much. I'll post it up here as soon as I can.
