Although I am sad to see that Sam is no longer the tooled up "techno ninja" he once was, I can understand why he is how he is now.
SC was ace. Pandora Tomorrow lost it's way a bit and Chaos Theory was the best. Double Agent wasn't bad, but I didn't like how they threw in the reputation thing - the missions still had the feel of Splinter Cell, but having to do things a certain way (and having missions in between missions at the base annoyed me).
The demo for Conviction seemed too easy. Knowing that if you perform a melee kill you then basically get 3 free one-shot kills of the next group of enemies dilutes the tension. I hope that the whole game isn't built around "1 easy melee kill, then a group of enemies for Mark and Execute". I did notice that you could mark your targets before performing an up close kill which means you can make Sam look as cool as he obviously is, even if you're a bit rubbish yourself. It all looks nice but still feels like they've dumbed down the gameplay for the more casual gamer.
In the end though, it's still Splinter Cell. You're still Sam Fisher (am also hoping that the co-op mode is old fashioned "stealth or die" gameplay from the first games, making at least half of the game a good challenge) and you still get to hear Michael Ironside offering remarks as you progress.
Since the first one, Splinter Cell has been one of few games that go in my "buy without any doubt" category. It hasn't changed yet.