I own and have played all previous Hitman games.
Out of those, i'd say Contracts and Blood Money were the best in terms of functionality and stealth mechanics. Contracts' revival of several older missions from the previous two games were pretty awesome.
Somehow though i have to say i enjoyed Hitman 2 the least, because it was simply impossible to sneak up to somebody who was moving around (and there were almost NO static guards, which isnt a bad thing, but gets worse when you cant approach them to take them out).
I very much enjoyed trying to take every guard out without getting detected in Hitman 1, so that was a bummer. Also the score system which rated you and gave you a rank for each mission kind of turned me off from my style of playing that i had developed in Hitman 1, and i rather disliked it in every other entry as well, though i can see why many people would love it.
For me though it simply made me feel bad when i tried to kill all the guards because i'd get ranks as 'deranged lunatic' or whatever, while that was the most fun to do.
Blood Money's newspapers were pretty awesome though.
Anyways, i'm kind of weary about this new Hitman.
When that movie came out (which was an absolute abortion cradled in filth) there were rumours that the next Hitman game was supposed to be more similar to the movie.
Apparently that was also the reason why they made #47 die in Blood Money (even though there was the possibility to revive him via an easteregg so you could shoot everybody at the wedding). At least, that was speculated about.
Several newsposts quoted devs saying: