A friend of mine brought a rubber/nylon type of pack one year. By end of trip the rough rock landings has started abrading the bottom and by end of trip it leaked.

I'm sure some mfg has addressed this issue but I'd keep it on mine if you go that route.

Another thing we noticed was that even if you put wet clothing items in separate plastic bag, the moisture/mildew/odor built up in it because they can't breath like a regular pack does.

You can use those sturdy/cheap pack liners, roll them down tight and put wet items at top of pack.
They might not dry out but the excess moisture has a chance to escape.

Another thing to consider is if you would tear a pack and need to do a field repair.
I carry surgical suture needles that in a pinch using some braided fishing line could stitch up a canvas/nylon pack.
Those totally waterproof packs are electronically seamed and I'm not sure how a conventional stitch would hold :-/