If I love YS 6, O, and F but absolutely HATE 7, will I enjoy this game?
As someone who also likes Felghana and Origin but didn't care much for 7 at all, I'd say probably not.
Granted, I'm only about 3 hours into 8, but so far it seems to have retained every single design decision I've disliked about 7.
The heavy focus on story and cutscenes. The overpowered consumable items. The pointless RPG systems like crafting. The skill system. The 3 member parties. All of that is still in Ys 8 and all of these things still drag the game down.
Worst of all, the combat system is still heavily based on dodges and parries, which means the only thing that really matters in combat is how well you can time those.
The windows for a successful dodge/parry are shorter this time around, and parrying in particular isn't as broken as it was in 7, but that doesn't fix the core issue of every single boss fight coming down to one single thing: how good your timing is. After all, if you can beat every single attack by just doging/parrying, why bother doing anything else. Especially since a successful dodge also buffs your attack speed.
Maybe it gets better later on, but so far my initial impressions are pretty negative, particularly for something that's supposed to be by far the best Ys game according to some fans. And Origin and Felghana didn't need 5+ hours to get good.