I do use a backpack right now. It's a pain. And I don't want to then have to dig through that backpack or my inventory to figure out which key I just used so I can drop it. What's the problem with just having them go away?
A key ring sounds great - I like anything that gets junk out of my inventory without having to jump through hoops.
You don't need to dig through anything, keys use themselves, you don't need to manually do anything, just store it or if you know the key has been used, drop it.
And while some may think backpacks are a pain, etc., be assured, once full game release, one of the best used mods out there will be a backpack mod for the various items, etc., just like it was with DOS2.