Like it has been said - 90% of side quests (excluding those with ties to main characters (Keira questline, Lambert quest, Skellige throne quests, etc.) dont offer anything new. The quality of writing for those quests (characters, motivation, the quest itself) is very high on average, but they simply dont add anything relevant to the game - and the pacing of the main quest suffers terribly from it. Take your regular witcher contract - you get a good set up, good encounter and a satisfying resolution, but in the end, it all boils down to "ugly monstah killed someone, gtfo and kill it". Its not that sidequests are bad, its that they are completely and utterly forgettable - thanks to their overwhelming quantity. I did all Contracts (and every single sidequest, treasure hunt and PoI, for that matter) and I cant remember a single set up or differentiate between them, and it hasnt been a full month since i completed the darn game.
PoIs are nothing short of atrocious tho, and "you dont have to do 'em or side quests" isnt an excuse. If its in the game, it has to serve a purpose. Do PoIs ruin the game? No. Would the game be better if they didnt put 'em in? Probably not, actually - PoIs were added late into development cycle since the open world felt "empty", thus, PoIs are nothing more than a repercussion of a badly designed open world - they literally went with quantity instead of quality. The zones are beautiful, yes, but there is no way in hell you can differentiate between one part of Skellige from the other - there are no subzones or landmarks worth remembering, which, combined with vendor trash loot and quest compass, makes the gameworld itself an empty landmass you cruise across, with no inherent desire to explore it, since there is nothing to explore in the first place. Compare it to way smaller worlds of Gothic 1 and 2 - they are both open world games, but they chose their size carefully, intelligently planted shit around, tied the game world with quests, etc., thus I still know every god damn nook and cranny of 'em, by heart.
While we are on quest compass - its one of those trends in modern gaming that needs to go, asap, we all know that. Sure, you can turn of the quest compass but that solves absolutely nothing - the game was still designed to hold your hand, not demand intelligent engagement. I turned my mini-map when I started the game, tried exploring the world "naturally", but in the end I'd pretty much spam minimap so I could see in which direction the quest marker is leading me. The game was simply designed with quest markers in mind, and turning them off is akin to watching a colored art house flick in black and white because "it was supposed to be like that" and "its bringing out its artistic integrity".
And all this is coming with an absolute Witcher fanboi, who thinks the game is nothing short of a masterpiece, even with the problems i listed + those i didnt - terribad combat, terribly handled save game transfer, lackluster game design in general, etc.
Just to illustrate the worst fault in the games design - I vividly remember a quest in Skellige, "Lord of Arena" or something. In short, local village arena is closed, since a cursed ghost has been haunting it for quite some time. The poor fella was a regular fighter while he was alive, and he literally never defeated anyone, getting humiliated all the time. Thus, his tortured spirit is still haunting the god darn place. Everyone and their mother has defeated the poor sods spirit, but he keeps coming back, against his will, cursed to get humiliated again and again. So, when I got the quest, i decided to beat the crap out of him with my all-powerfull witcher mojo - he surely aint gonna cum back when i bitchslap him. So, I bitchslapped him, rested, and whaddya now, the son of a bitch came back. Tried once more, same result. Quest tracker just said "Find a way to permanently remove the spirit." Not willing to fuck with a trivial sidequest any more, I just googled it. Turns out that a "trivial sidequest" is actually best designed quest in the game - to remove the curse, you have to let him beat you. But it was the first time that a 100h+ long game demanded from me, the player, to think, not just spam light attack at marked monster, thus, I didnt even contemplate the possibility that the quest solution was anything but the usual quen, dodge, light attack, dodge bullshit. Surely, I just needed to collect some stupid quest item and bitchslap him harder.
With all that said, the game is nothing short of amazing, really. Its phucking beautiful, the soundtrack is superb and the writing, together with its presentation (voice acting, cutscene angles, etc.) is among the best the medium has ever seen - but never before with this kind of visual quality and technical advancement. The story (plot, characters, dialogue, thoughts, setting) is undisputedly remarkable, which, coupled with its amazing presentation results in one of the most emotionally powerful vidya experiences, ever. And if you think "emotions are fur gurlz, lul, fag" then you dont really care about art, buddy. Which is fine I guess, its just that we arent ever going to agree about any game (or anything else, for that matter), ever.
Mind you, Blood and Wine is an improvement upon the base game, in every aspect, which is why i harbor high expectations for Cyberpunk. And, I just have to say it - with all praises I just sung to games writing, base Witcher 3 main plot could have been handled better. Not that it matters much tho, the game has way bigger problems than that.