Putting it on "Perfectionist" difficulty makes it play a bit more like classic Splinter Cell, but there's a constant feeling that I'm not playing the game how it's meant to be played. It doesn't feel organic, it just feels like I'm holding back, and restricting myself from the game's features. It usually doesn't afford you enough options to remain hidden and avoid enemies, as the levels just aren't designed that way. It makes pure stealth more frustrating than enjoyable, and the lack of any quicksave really amplifies the trial-and-error of it all too.
It offers some verticality in the way you traverse environments, and it does gives you a few choices on how to approach different areas, so it's certainly not linear... But most areas are pretty restrictive and seem more designed with cover shooting in mind. Even when you are stealthing around, you're awkwardly moving from cover to cover, and there's no stalking your enemies, because it feels like they can spot you in a moments notice. It's closer to "Gears of War with stealth" than it is to classic Splinter Cell, and changing the difficulty level can't change the game design. There are a lot of bright levels, there are no incremental adjustments in movement speed, no light meter, no sound meter... If their design philosophy isn't clear enough to you, there's a point of the campaign where it turns into a first person shooter, just to drive the point home.
Splinter Cell is dead, and has been for a long time. Whatever this is, it's certainly not a bad game, and it's better than Conviction (which isn't much of an achievement) but I'm done with the series. Clearly Ubisoft is too, as they keep insisting on morphing it into something completely different.