>>"good basic pack wt. goal" AND "anthing else in pack design"
two versions - both top-loading draw-cord, roll-top closing made of one piece of material - if possible, so, only one sewn seam to leak.
one for on trail use. so, the GG Mariposa is the de-facto standard, IMHO. therefore, 16oz with CF stays for a frame.
the other (being essentially identical in design, volume, and features) for some off trail exposure, scrambling, etc. (perhaps not full-fledged "shred-o-matic" bushwacking). a heavier fabric with a Spectra "rip". think, SMD StarLite - perhaps also a de-facto standard (my experience is limited). so, 24-28oz wt in this heavier-duty version. here, my thought is more "a robust fabric" rather than pure load carrying capacity.
external pad pocket - could be velcro (?) closing instead of the SMD zipper (hope i got that right). leave a small opening in a corner & top center (POE pads) for inflatables to be inflated after insertion in the pocket (and the pocket being closed). POE pads - would these be comfortable carried in the ext. pad pocket with its valve being "amidships" along the spine??? perhaps a small neoprene/closed-cell attached valve "cap" is needed (this is getting too complicated).
over-the-top 'Y' shaped compression strap (keeps roll-top from opening), and one circumferential compression strap maybe 2/3 or 3/4 of the way up the pack (not including the height of the exp. collar).
personally, i don't see a need for "hydration ports". it's very easy to route a tube out the "cinched" opening, position it laterally and roll the top closed around the tube - then secure with the compression strap. tube exits fine and can be easily routed. this works well for Platys, IME (in my experience), but some bladders have a shorter tube and these might not work well. it gets tougher if exp. collar is fully extended. in these cases, might have to carry bladder in a side mesh pocket if tube is too short.
somewhat voluminous hip-belt pockets, certainly no smaller than the upcoming SMD Essence. BOTH fabric, NOT mesh.
large front and 3 side mesh pockets (2 small+1 large - on opp. sides of the pack, of course). the lowest small side mesh pocket should be as close to the extreme bottom of the pack as permitted by the design of the shoulder strap attachments, so as to permit easy retrieval by those with short/tight shoulder capsular ligaments.
bungee water bottle holders on the shoulder straps.
optional chest pouch (similar to the MLD Prophet's & the GoLite Team pouch).
i'll leave other aspects of the suspension fine points to those far more knowledgeable about pack design than i am.
i purposely left out ice axe/tool loops. i don't use them. i'll leave it to others who know about these to properly explain a good design for these.
oh...possibly, some small webbing loops to permit a custom bungee arrangement if desired. 6 or 8 total - half on each side - NOT sure how to do this if you only have one seam, as i suggested up top - so these may need to be left out.
Bill...you're sorta' like Santa and i'm a kid giving you my "wish list" (you know, like...3 pages long!!). Hope you have a lot of Elves working for you. oh...i've tried to be a good little boy over this past year!