I believe this product is focusing on storage space, being small enough so that you would have it in a smaller kit you would actually carry. The combo you suggest would be quite a bit bulkier in your kit. This vest is not the best item to have for hypothermia, but I believe it does meet it's objective. A polypro balaklava with gore-tex hood would be a good addition as would many other things. With all the kits you may envision, you need to choose between bulk, utility and odds of needing that category of gear. This fills a particular nitch, but may not be an item you choose to go with.

Here's another write-up:

http://207.210.105.72/~halcon21/forum/index.php?topic=567.0