I can understand having difficulties when connecting with set protagonist, esp. of another gender. In my case books helped a lot.
When I first tried to play Witcher 1 I did not like it at all. Geralt was boring to me, combat clumsy. Then read the books, fell in love with the universe (slavic mythology and folklore, yes, please!) and the characters. Geralt, Ciri, Yen and their friends and enemies made me care. I went all the way with them through the books and then through the games, and it was a wonderful journey with an ending that made me smile.
Just to think I could miss it makes me sad. I will definately replay Witcher 3 making other choices.
It doesn't mean I have absolutely no problems with W3. Some of them are small annoyances (auto-sheathing, no storage chest, inventory is a wild mess) which I hope will be addressed in future patches. Some are big - wtf moments with Sigi and Radko, aftermath of the game, and it felt like Reds went really wild with placing all this smugglers stuff on Skellige.
But overall it was a very positive experience.
Things that I liked in W3 more than in DAI.
1. Athmosphere of a very alive world reacting to your actions and having a lot of interesting things to do: hunting monsters, taking part in scenic perfomances and tribal rituals, playing cards, exploring.
2. Sidequests - a lot was said about them already (different choices, moral dilemmas, interesting twists, consequences and connection to the world).
3. Novigrad - a big town filled with different activities. V-R was... just 2 screens.
4. Mount is useful (horseback combat, terrain is horse-friendly and our horse has a name. I know it's a tiniest thing, but we could name our mabari in previous DA games, why not a horse?)
5. Music. Beautiful, with national color (slavic and gaelic) used not only in the cutscenes but also while exploring and during combat. I think the deliberate decision to make DAI music only sound for 5 seconds was unfortunate.
6. Hair. Not only the quality of textures, but hairstyles themselves. I liked medieval aesthetics, not a fan of DAI bald and shaved, too modern.