The original Deus Ex was a lot of things to a lot of people. In fact, that was pretty much the whole point: it was a game where you could save the world by shooting all the bad guys, but it was also a game where you could save the world by hiding in vents. The levels all had lots of different paths through them, and the gameplay systems were designed so that you could combine and experiment with them to make progress. Whether or not you played it, Deus Ex was responsible for a lot of the good things that you have spent money on in the last decade.
Sometimes, Deus Ex: Human Revolution is just the best Deus Ex tribute act ever. You can still save the world by crouching behind desks and hacking into people's email if you want, but it doesn't judge you if you want to do something else for a bit. In fact, it rewards you. It gives you an XP bonus for not being seen, but it also gives you an XP bonus for brutally incapacitating two guards on patrol with the same takedown.
There is no wrong kind of progress, there's just success. It would be nice if more of the games that wished they were Deus Ex treated us like that.