So this is a dream-post. I don't think it will come true, but if anyone could do this one right it will be Tom and company. I blame my son's Brain Bag, which got me thinking about this.
I've seen oodles of picnic backpacks on websites and in person, and they share some common issues.
First issue - side-slung wine-bottle pockets. Great idea, but almost always terrible execution. If there's only one on one side, the pack balance is horrible. Two pockets are great, but a bottle on each side adds quite a bit of weight. On my son's Brain Bag, the center-clip allows a way to carry a ring-top bottle without mangling the pack balance. Uninsulated or half-high pockets mean you can't keep chilled wine cool. Can the material that keeps computers from harm also serve as insulating? Is it too stiff to make a tube out of it? I don't have a TB Brain Cell, so I've no idea
Second issue - poor, poor strap designs. Adjustment points that slip when you pack a full pack are useless, and I've never seen one with a chest strap.
Third issue - a picnic backpack usually comes with plates, cups, utensils, etc. Most of which are kind of junky. I'm not suggesting that TB run out and find suppliers for all this stuff. Can inner pockets be made to fit standard sized items, so that the buyer can pack their own 'furnishings'?
I have NO idea how this could be designed, but thought I'd throw it out for consideration.