Dunno - In My Not So Humble Opinion - what you are trying to do (one uber perfect pack for all situations) is going to cost a lot of money and possibly leave you unhappy in the end.

In a nutshell you need your pack to carry what you need to carry. I carry different stuff depending where I am going, what time of year I am going there, and for how long.

This is why I think it's better off to have a couple of different packs, more suitable to what you are actually doing. I have three I regularly use. Too many people seem to fall for the "Well you should get this in case you end up going to Alaska for three weeks/Climbing Everest/Winter Camping in -40" and end up with something huge, modular, and expensive that two things more fit to realistic purpose would both work better and save them a lot of money.