Mostly I'm just annoyed that the majority of the spells vendor sell are spells you CAN'T use yet. I'm level 3 or 4 and looking for things like ice shard, or bless, but no, it wants to give me 90% level 7 or 10 spells. so I have to wait forever just to get the spells for my level. I find this silly as I've gone some playthroughs not getting a low level spell until I'm level 7 or 8. And this is with consistently checking the vendors every time I'm in town.
Perhaps this is just a downside to RNG. Before they had the vendors selling too many duplicate spell books, but at least you could find the spells you wanted a lot more consistently. Now I find it hard to do.
/this! very much so.