If your worried about something leaking, i.e. a hydration bladder or fuel bottle, simply put it on the outside of the liner bag, between the liner and your back, inside the pack (for the bladder), or on the outside of the pack in a pocket.
wet clothes? after you roll the bag shut just lay them on top. Or better yet strap them to the outside of your bag, giving them a chance to dry.
One of the principals of ultralight is not carrying more clothes than you can wear, so you might actually be wearing the wet items, and body heat is a good dryer for synthetics and wool.
It really fills the space effieciently, not having the stuffsack. I used to do like Ben, everything in bags, for organization, and my bag was a lumpy looking mess, and hard to pack. Now I stay organized by having fewer things.