I don't doubt that it's a great game, but it's weird to hear so many people that adore the game also straight up say so much sucks about it. It must have some REALLY cool shit in there.
I'm glad I didn't succumb and just think that it would be good enough to just make me inherently like it. I've learned that games like the Witcher 3 just aren't for me, and that's ok. I understand why others would like it, but it's not for me.
Bear in mind the only real, major complaint is the combat. That's ubiquitous. The other complaints are generally more specific/more from a minority. For instance a lot of people say it has open-world bloat, which is something I get badly, from games like Skyrim/FO4/Far Cry/Ass Creed. But I haven't had it once with The Witcher 3. It's fantastically designed imo. There is one part where the pacing can collapse (not enough to do in the major city), but aside from that.
Broadly, though, it confuses me too when people go crazy about the combat. I
think it's my GOTY (amazing year for me), and of course I'll admit the combat is flawed - but I'd never say it full-blown sucks.
The combat spends most of its time idling at 'servicable', and occasionally swings to the 'fantastic' side (when the rhythm really lands and you really feel like you're in Geralt's shoes) or the other way into 'bad' (eg when the encounter design has a mis-step or you play against a badly designed enemy type who can stunlock you with ease).
I'd say it's servicable 70% of the time, fantastic 20% of the time and
very bad 10% of the time. I'd never say the whole system is bad, it is just flawed at a very low level. On top of the core movement/attack flaws, it gives you loads of strategies and options for dodging frustrations, so usually it's fine.
What's telling is also that you get people who say 'combat clicked for me straight away, beat the whole game quickly on Death March' then those who say they are big BB fans but say 'combat sucks, badly balanced, always too hard' etc. There is an overlap, but a lot of the time people just don't seem to get into the combat. TW3's combat is about being the character - about using the monster hunter clan's tools to swing fights into your favour. It's not about truly skilled moment-to-moment gameplay.
Out of curiosity, what makes you think it's not for you? I'm not a big RPG man and I have a lot of dislike for Skyrim and most other fantasy RPGs I can think of, but The Witcher 3 is more like a gaming equivalent of HBO's Game of Thrones. The world and mechanics are just compelling and intricate and
real enough that it's a sublime world to immerse yourself in, minor gameplay qualms aside. That's why people (me included) rate it so highly.
When I boot up TW3 I feel more like I'm loading up a couple of great Game of Thrones episodes - I'm living in this great, holistic, realistic fantasy world for an hour or two, and it perfectly captures that feel. Even if my session just consists of progressing a quest or two through dialogue with characters (no combat or exploration) it is so well written and I like them so much that it's a really satisfying session.