The story is complex and the action is plentiful, but Border 4 isn't as satisfying as the other three. The music didn't fit the visuals a lot of the time and the animation occasionally seemed rushed.
There was potential for dangerous hesitation and second-guessing of thought and actions (had their own memories been altered, and/or could they still trust the 'whispers' from their ghost?) but it went in a different direction - a direction that's still a very recognisable part of the Ghost in the Shell world, but a less dramatic one than I feel it could've been.