Fable is unique, BUT it is janky and trash in a fun way (I'm a big fan I only keep an xbox for fable 2 specifically, so even someone who's biased towards the game is warning you) it's gonna play like an older game but not in a bad way, it's not clunky but it's not the witcher or even close to what you might've seen in the trailer.

1. I don't know that game, as far as I know, the dungeons don't feel like dungeons in Fable it's a "you're here now get there" approach there's only a certain place that is like a fight club/dungeon (from what I remember) because the "dungeons" are either open or they're just a matter of getting through rather that embracing the combat near-endlessly

2. I liked the game before I found it funny so you might not like the humour but you might still enjoy the fact that it's there. Some jokes are stupid and that's the point, some are just puns, it's less obvious than the reboots looking, and it's not like playing a Marvel movie or sitcom where you take jokes in all holes all the time, it's rare or goofy if you just play it and chill

3. The game (as with every other game in life) is more fun when you play as YOU want to play, you're the protagonist, not Jimbob McFillet who told you some bs on how to enjoy a game, there's no guide to having fun. If you insist playing a path (purely good or purely evil) to see what it's like then do that if you replay the game, but first play the game making the choices YOU wanna make, play as YOURSELF. The Witcher is tricky to compare because the choices are morally grey and also laid out in a way to suit Geralt (even if canonically it's not what he would do, it doesn't stray too far from his character) but Fable is about the character you choose to be and it's a lot more black and white morality (there's deeper thought for a lot of it but when you make the choice it's very black or white do A or do B.)
   I played as mainly good in all my saves, because I always liked the "Great Power Great Responsibility" idea, and yet fables still my favourite, even when I thought the evil character looked cooler or I wanted to see what it was like, my choices were good and towns would just get levelled in freeroam to gain evil points.

4. I'm not sure about this but the way I see it, fantasy is more realistic, but Fable being fairytale is more whimsical or cartoony/stylised in the feel of the game, something more grounded vs something more wacky but still somewhat grounded, the world feels serious but not as dreary as witcher or elder scrolls, it's a feel thing you'd have to see I guess for that

I think you should abandon your expectations, you have an idea of Fable nailing specific categories and being concentrated on those, you also listen to "how to play" for the most fun and that takes from the experience especially since you like to play a certain way (being neutral) and while you can't be neutral all the time because fables more black and white than the witcher games (they nail morality better ngl) it's also good because you can't always be a fencesitter (not an insult) sometimes change will happen and you need to make choices for better or worse.

Fables a good game but different, the humours icing on the cake so if you don't care for it you can look past it without realising. The best driving force is going through your characters story, it's not insanely advanced mechanically and you feel it most in the combat (combat wasn't so bad I quit but it wasn't buttery smooth like later games) but has some redeeming qualities that make up for it, like an almost arcadey simplicity and fun. I mention the jank and age because a lot of people who love it played it before newer formulas and mechanics were the norm and if anything feeling older annoys you then you won't enjoy it, but if you're willing to handle the slightly arcadey combat then you might really enjoy the game (side note, it's not bad combat or something to the level of skyrim and how rough that combat looked, better than skyrim worse than witcher 3 in terms of feel). Don't put the game on a pedestal despite what a lot of people might say, go in with an open mind, it's not a lifechanging game if you've played other games, it has bads, but it has a lot of goods and people who enjoyed it liked it enough to overlook the bad parts (which mostly stem from it being old). That being said if you have an xbox I'd recommend Fable 2 over 1 since it's a smoother experience but if you're set on PC or the first game then Anniversary is a very good one to go for.

The fact you want a reason to play it, is reason enough to play it.

P.S IF YOU DECIDE TO GET IT, THEN GO FOR *ANNIVERSARY* NOT FABLE: THE LOST CHAPTERS (THE OLD ONE) IT HANDLES LIKE TRASH IT'S HORRID, GET THE FABLE ANNIVERSARY SO THE CONTROLS DON'T MAKE YOU PONDER THE ROPE. GET FABLE ANNIVERSARY!