No actually I thought that sidequests are one of the weakest point
first of all, they all fallows the same pattern and involves too much guiding/handholding which alone disqualifies them as amazing or even as remotely good,
acquire quest -> fallow markers and go to places A and B which are also marked on your map -> press E on every glowing object to win the quest,
the game even constantly tells you what to do in every stage of the quest. for example massage prompts ->go to a place -> now explore this area ->now talk to this person and so on
there is no satisfaction and brain work included in solving quests because Geralt tells about every clue, reads every note and book relevant to the quest and reveals what these clues might lead to, when you press E, for you
you rarely face any obstacles except few trash mobs, on your way to finishing the quest, like NPCs who wants to distract you from finishing the quest for some reason, or NPCs who somehow are tied to the quest or interesting enemy encounters
side quests are very short usually takes about 3-15 minutes to complete, areas and dungeons you visit to solve the quest are very small, linear and takes less then 5 minutes to explore, filled with few trash mobs and more or less worthless loot, so there are no huge maze like dungeons and underground fortresses filled with valuable loot, interesting enemies, encounters which requires smart decision making, items and people and so on
usually problems presented in quests are tied to separate individuals (for example, find something for a smith, kill monster for a farmer, ect.) and not tied to communities and settlements as a whole, so forget about epic "save the village whose inhabitants are shackled by fear, because evil witch from old times, somehow arise from its grave in deep forest and threatening their very existence" and something like that
they starts in the same fashion, that is you have to talk to NPC or read a note to acquire the quests, you cant for example run into quest, or find a clues somewhere in the world that doesnt instantly gives you quests and after some time find another clue and when going into some area and then knowing about the quests in that area from the clues you acquired, or quests that are not immediately unlocked but starts only when you advance or finish other quest and you have to make ends meet or something happened in first quests that affected the world or something like that
also quests dont interfere with each other and are not inter-connected they scattered around the world without any imagination waiting to be resolved
and they really are so tedious and monotonous and repeating you feel like trash man collecting sacks of garbage throughout the area
there are hundreds of quests in the witcher 3 but you can sort almost all of them into these 3 fallowing categories:
kill monster (either through a contract or NPC)
find something (usually people) for other person
find lost goods, which are few steps away from the area you acquired the quest
and repeat these 3 again and again around the world, by going to marked place and pressing E to win this quests, ad nauseam
and these quests are so shallow too as I said you almost never encounter anything interesting other than: go to a place - kill monster, go to a place - find something, go to a plce - acquire lost goods
short, requires no brain work, small, easy, guided, isolated form each other like frozen pizzas in supermarket
this is literally fast food of quests