At first I hadn't understood the random mechanism for shops, I quoted it for chests through some reload, but from shops it wasn't clear until I made a wrong click stealing something instead of just moving the party. Loaded back and realized all the nice items I just bought in shop had disappeared.
It felt frustrating and then I started some tedious save scumming from shops. Later I gave up but for skills books. It's just wrong that they are so random when they are closely linked to characters building. That game just doesn't have the random diversity to justify it.
I don't like the Diablo like loot system (and share preferences of OP) but I feel that players like me and OP are in a small minority nowadays. I don't like the save scumming but I bet some players appreciate have a tool to cancel a bad random. But the random for skills books is purely wrong.