Which is weird, because the Thief games have not been continued for quite a time (fingers crossed a new game is currently in development) and Splinter Cell was dumbed down to much more run&gun.
Thief 2 is one of my favorite games of all time.
The difference between Thief and sneaky, stealth games now is
1. Thief involved more skill and was much more unforgiving when you made a mistake
2. Thief takes place around Renascence era, and doesn't have any cool gear, like cloaking fields, night vision goggles or silenced ballistics weapons. Also doesn't have cool, animated death sequences and attack moves.
3. It was also a PC only game.
Thief was more about actually playing the role of a Thief, whereas games now are about being a sneaky one man army.