One point to make here:
You can complete the quests before getting them as the game does not spawn new items or enemies just for quest purposes. It stops you from killing all the boars, for example, before you take the quest to kill the boars, only to find they are all dead...
Unlike skyrim, where killing certain "bosses" before you are on the quest , so they don't drop the quest loot and you then vcan never complete the quest... This happened to me on several occasions.
You still have to find the NPC to get the quest, and van then tell them you have already solved there quest. Simple and less prone to bugs.
Oh, and you are also comparing a large budget large studio game with a game ported from a pc version where the developer is tiny, really small, and has no where near the cash of a triple A title.