I both do and do not get the hate for Witcher 3's combat. It definitely has issues but I really feel a lot of those come down to weird imbalances, general performance / responsiveness, and enemy specific design inconsistencies. Leshen hitboxes, for example, are awful for their attacks and I have no idea why CDPR hasn't fixed them yet.
Otherwise the combat feels pretty great to me. To be fair, playing it on a high end PC where the framerate can hold up does wonders. That extra responsiveness, or at least the illusion of such, with the smoother framerate compliments the somewhat sluggish character motions, making engagements feel far less frustrating.
RE: Elder Scrolls / Bethesda Fallout. I can totally see the appeal; Bethesda essentially built limitless RPG sandboxes with a ton of attribute and function safety nets to encourage freeform play, and folk love that stuff. They're pretty unique in that respect, and there's not many games that offer similarly relaxed, open experience where low risk agency is the cornerstone of world interactivity. You can literally just boot it up and go wherever, do whatever, and not have to worry too much about consequences. Comfy gaming, balanced with carrot-on-a-stick progression through levelling and gear.
I personally find that a bit boring though, and it's not what I'm after in my RPGs. I like more complex interwoven game systems and statistics where player agency and character speccing resonate with a reactive game world, as that to me is what role playing is; envision who you're going to be, and see that recognised, through strengths and weaknesses. There has to be some game system causality, and it's highlighted in stuff like New Vegas over Fallout 3, despite sharing the same game system template.
Plus, you know, the stories and what not. They're all fucking boring. Bethesda's writing is so dull. I feel no lure of engagement or presence. And I mean, Wild Hunt is objectively a less agency driven RPG than TES. Your scope of world interactivity is far more limited. But the writing elevates the simple game design over everything else. I can actually, you know, remember shit.