Say what you want about Jorvack's madness, but his methods have some validity...
However I'm most interested in a bivy that will be truly waterproof... going to bugaboos, tuolumne, NCascades, etc for a couple of spring/summer/fall days, want to to stay really light, may have to deal with afternoon showers. I'll carry an extra 7 ounces (MH Bivy) or an extra 11 ounces (WT) to for full waterproofness and some weather protection. The idea of an overbag sounds great for colder temps, and the bibler looks great for snow stuff, but 3-season superlight waterproof coffin sounds like it would be a great addition to the closet of gear that's really only used to sleep out next to the river at Index.