I never played SO4 so can't really comment on it. But the game feels very barren and simple (huge, dull, lifeless environments where enemies wander aimlessly) and there's lots of stuff that feels quite jarring (for example, there's no animation for opening a door the game just pauses while it loads into the building). The most obvious sign is that the cutscenes aren't cutscenes - dialogue just happens in the usual game camera while everyone stands around and you can't move away very far. It all just adds up to create the feeling of a game made on a tight budget.
I didn't get far enough to experience a lot of it, but the game also apparently suffers badly from reused enemies, backtracking through areas multiple times in the game, and the combat never really gets particularly fun or interesting.
As a positive, the localisation is actually pretty decent and I don't mind the character designs and faces etc that many people complained about prior to release. Overall, it's still a pretty bad game though lol. I was so disappointed because I'd been looking forward to it since it was announced at E3 last year.
it's the best game of the year, until the sequel is out.