My pack desires:
--Top-loader. You can load them more full, everything is in one spot, they are easy to waterproof everything (just line the main compartment with a heavy duty trashbag)
--No zippers for the main compartment. (I don't mind an internal pocket zipper or a pouch zipper but no zippers on anything that matters.) And the zippers used should be those heavy duty #10ykk type.
--Somewhere in the neighborhood of 2,500 cu in. That way, I can live indefinitely out of just this pack.
--streamlined on the outside. I don't mind a couple of pouch style pockets (one to hold a nalgene, one to hold dirty underwear,is sufficient) but no straps, bungies, tags, 8 handles, ropes, and whatever else these crazy designers use to get you tangled up on trees, crowded kombi's, trains, etc. I'm sure I'm in the minority here, but I'm not interested in molle. If i need to strap a bunch of other pouches on it, I'll just get a bigger pack. Maybe a small strip right down the middle of the pack.
--if it must come with a waist belt, I want it removable
--if it has a sternum strap, it should be made of webbing and not elastic. Elastic always wears out and looks crappy. I'd prefer no elastic anywhere, come to think of it--like water bottle pockets, etc.
--I have no need for a laptop sleeve, a hydration pocket or anything else that looks good on paper but only adds weight and takes up space over the long haul.
--Don't really know how to articulate this, but I'd prefer the pack to be tall and narrow, rather than short and wide. I find it better to have the pack run the legnth of the spine, rather than be low on the back and so wide, it sticks out on either side of your body to catch on things. Because it is more narrow, I think you could do away with compression straps to keep everything tidy. Also, because it is tall, I can wrap my crash pad around the inside to provide structure and still close the lid.
--Buckles should be heavy duty plastic, no metal (ex. No metal button snaps).
--Here's the tough part--I want it to be incredibly durable but not look too tactical. As such, I need absolutely NO velcro on the outside. I'm not planning on sporting a "Bang One, Bang 'Em All"; "Pork Eating Crusader"; or "Suck Meter" patch in the Amman airport.
--incorporate some sort of hidden pocket somewhere for papers, documents, money, etc. RYP knows what I'm talking about here. Maybe somewhere in the reinforced bottom--a space between the two pieces with a velcro strip right where the side seam would be so that when viewing the empty inside, you don't notice it.
--It would be nice to somehow create a pack that has some ventilation between your back and the pack itself, but it's not a deal killer and if it adds to much weight or bulk, just scrap the idea. I have an Oakley pack that does a decent job at this, but nothing I like enough to copy.
Those are just some of the things I've been kicking around for awhile. I'm very interested in seeing what Robert comes out with. He has a very good head for gear.