In one word: boring
It's the only reason I'd consider using cheats. Traditionally this is handled by either not allowing items to the inventory or speed handicap. Perhaps it's time for a new philosophy?
It is, of course, realistic to deploy either of methods above, but it makes it less enjoyable to me, alas. On the other hand, a character that is runnning, flying, jumping through the gameworld without (a) visible backpack and (b) never losing anything on the track? Come on, that's no realism either.
When comparing the Witcher (1) and Skyrim, I see that in both a limited inventory space is allowed, and both can store items elsewhere. If I'm not mistaken, in the Witcher only a tavern could store up and even this was limited space, whilst Skyrim allows the player to store virtually any amount in numerous chests, vases, carcasses,...
The last one is an example of "even more irritating due to compromises". If you HAVE an unlimited storage but you have to RETURN to it each time you find something worth keeping, then YES you spend 10% gameplay hopping from storage to exploring and back.
So the Witcher was harder. There were NO compromises. You had to carefully decide what to throw away. The designers were clever enough to have the 'source' and 'destination' storages in one screen, so that overview and transfer were geronimofast.
I have no 'realistic' alternatives, but now you know one reason why the Witcher >>> Skyrim.