edit: @FenrisC
I'm confused because the game gives you those filters already. I can either display all or decide to only see gear, potions, books etc.
How does the allocated bag idea improve what is already there? I don't mean to talk down your idea, I just really don't get it and here to learn.
The idea is to have a clearer representation of what items you have and where, without having to constantly hit a "filter" or "sorting" button : this way you'll have a nicely organized backpack by separated sections, and will immediately see what new items you got into since you'll control where on the screen they will be placed.
Sorting and filtering function - heck a search one as well - will be useful features, but if your backpack is already visually readable without, all for the better, dont you think ?

I like having things organized, managing inventory is always a pita in nearly all games I played, plus it's time-consuming.
Lets sort things at first glance, searching for specific item will only be easier.