You're right - as is, out of the package, the Lid is a poorly-designed add-on. It has plenty of capacity for me, but using it is a real pain. You have to loop the fastener through the compression straps on the back (or is it front? - I'm never sure) to cinch it down. As a result, the only way to get the pack open is to unfasten that loop (or unthread the strap) so the Lid will flip up out of the way. Extremely cumbersome at best.

However, there is an easy cure. Cut the long strap (the one attached to the male end of the Fastex buckle) loose from the Lid. Now take the "back" end - the other end from the male part of the buckle - and sew it to itself to form a small loop, just large enough to slip over the webbing on the compression strap. You now have a configuration where unclipping the buckle lets the male end dangle loose from the compression strap while the Lid flips out of the way. (More like a traditional top compartment works.) This actually makes the Lid convenient! Oddly enough, though, I tend to prefer using the Granite Gear Air Pockets to hold the stuff that I'd normally put in the Lid (maps, gloves, etc.), and store them in the side pockets - they fit nicely, and are now handy. By the way, a Platypus fits the side pockets much better than a Nalgene bottle, too.

Hope this helps.