The main problems with the prototype design we took to the Arctic that will be fixed in the version we'll ship this spring were:
1. Harness (shoulder/hip) strap angles are being adjusted to better distribute load at stress points.
2. The materials are being changed to be less abrasive on the body. The old packs used a very abrasive and heavy mesh that absorbed little water, but was pretty uncomfortable and abusive to clothing over the long haul. The new pack will will not change overall weight much, but undergo some materials changes to make it more comfortable while retaining excellent resistance to water absorbency.
3. The back pocket design is completely revamped. The old pocket snagged on brush, it was baggy. Water bottles, in spite of best intentions otherwise, couldn't be accessed. Because this is at heart, a "water" pack, the need for it to carry a lot of water and have that water accessible is limited. The idea is to have a place to carry your water bottle (empty) outside the pack so it remains accessible. On the Arctic trek, we just looped our Nalgene Cantene bottle caps around a strap. The new pack has a flat, zippered back pocket that's big enough for stuffing storm clothes (specifically, wind shirt, rain jacket, wind pants, hat/gloves), a thin water bladder (like a platy), and extra food. The bulk of your food will go in the huge hip belt pockets :), which are fine as well for camera, etc. Anyway, the new backpanel distributes the load so much better than the old one, and does so with one less compression strap (the new pack has 2, the old had 3 sets).
I'm really excited about the new design. I love this pack, and have been using it on "regular" trips since the Arctic trek, just because the dry bag concept makes life soooo easy on the trail and in camp. Gone gone gone are the days of dealing with pack liners, pack covers, waterproof stuff sacks, etc. I do still use some nano stuff sacks inside, but only for organization of small items (cook kit, essentials, etc.) and in dry(er) weather, I've been skipping them altogether for sleep and clothing gear, and my wet tarp just gets stored outside the dry bag, underneath the back panel.
Brian will send me his list of interested names, and those folks will be notified by email when the packs ship from Brian to us, so they can keep an eye out for the stock alerts.
If you want to be "on the list" when the pack comes into stock, sign up here for a STOCK ALERT, as this page will be the landing page for the new pack:
Arctic Dry Pack @ BPL