The makers of this anime classic apparently decided to go all George Lucas and "enhance" the visuals with new CGI graphics.
Most of the changes are to secondary things like the helicopters and computer displays. Things you never really pay attention to and don't really matter if they look a little more detailed or not.
They also took a couple of the landmark scenes (including the opening sequence) and redid it all in CG, Kusanagi included. On top of her looking like a Poser model and it being really awkward when they cut back to her in her original drawn form, the redone versions are composed terribly. Iconic shots now look really cheap. Often there's just more artistic freedoms in 2D.
Which do you prefer?
On top of changing graphics that didn't need changing, they also redid all the sound effects, and not for the better. All the guns now sound kind of out of place.
The weirdest part of all is that they've completely changed the prevailing color scheme of the movie from blues and greens to orange. Not only have I no idea why they would got through the effort to do something like that, it really changes the mood of the film from cool and mysterious to just sorta toxic and burned out.
Again, which would you rather look at?
I should point out I've never been a big fan of Ghost in the Shell. I do own it and recognize its influence on anime and on me as an animation fan, but I still think it's cold and confusing.
But despite all that, there's really no point trying to fix something that wasn't broken.