some random thoughts:
The game could really benefit from non-combat quests. A good example is the wedding quest in Witcher 3's Hearts of Stone expansion. There are a few, and most of them seem to involve Sokrates which may be why he's the most interesting character.
I hope they add alchemy in future installments. Bombs, potions, etc., Didn't origins have bombs? Wonder why they took them out.
The items are interesting, the engraving system is good... honestly, no complaints at all here.
I like that they copied the nemesis system from the mordor games, but they should have aped it entirely with returning(wounded) mercenaries that have a vendetta on you.
The game seems to waffle between wanting to be a history RPG and being an alternate-history -- I'm not really sure what to call it, sort of scifi I guess? -- RPG. They should just pick a theme and stick with it.
Honestly seems like Ubisoft took a look at the more popular games and decided to just copy the stuff that works from them. And it's not bad at all.