That is what has me confused as well is what to sell and not to sell. Currently I've maxed out my inventroy and can't pick nothing up unless I either drop, destroy or sell some things. But there is no way of knowing what can be dumped and what should be kept. And with allot of things going into the valuables and you not being able to sell individual items and have to sell everything in your valuables at once I'm worried about losing stuff for which I need.
We should be able to pick and choose what we want to sell and/or give us a chest where we can store stuff that we don't want to sell til we are sure whether or not we need it.
Another flaw to the game is that the inventory is pretty much the same for all party members. If one has say 60 items they all are carrying the same items. And it just doesn't make any sense to me why they would do this here.