... what's wrong with real time inventories? They make the game more difficult?
Honestly, my opinion?
Its actually the same as with realtime books. If you ever played diablo, then you have at one point been reading an item description, and been hit unawares (possibly even killed). The advent of realtime inventory was to originally solve the problem of players swapping out weapons (and in some games even armor), in between opponents during a fight. In Baldur's Gate this meant that you could slip into inventory and re-read scroll spell descriptions and by the time you found the one you wanted, most of your party was wounded or dead.
Eventually a non-obstructing inventory screen became the norm, (Diablo has this, and Arx Fatalis has it), but even so, its still a hassle and very unrealistic, and an unnecessary risk IMO. There is no reason to make the game more difficult for a non-game related task. If one must pretend they are the PC and realtime-rummage in their nap-sack, the better solution is hotkeys that they set and memorize; because the menu alternative is not an accurate depiction of how it would be; As the character would know where they put something and would just grab for it (IE best represented by a hot-key). No one would sit down and dig through their stuff
while a thing was beating them half to death with a stick (and if they did... they would not be scrolling though tabbed menus to find it ~meaning the delay is artificially longer than it would be because of the interface).
Players that read the menu based inventory should not have to bother with getting hit over the head while doing so. If it were really happening and they were really there they would recall the details; and not need to re-read them after a month of not playing the game.
In the absolute very least... The game should IMO allow the player to pause the game when in menus or books ~that would be the most valuable toggle addition that I have so far read in the forums.