You've missed the point of assassinations in Assassin's Creed 1 & 2, though. The whole idea is to be seen, to properly send the message. One of the so-called "rules" of the assassin's creed in the first game is: hide in plain sight. That is, basically get right next to your enemy without him knowing, something that Hitman does do. But Hitman is a lot more about stealthy stealth, whereas in AC, well, all your missions are in broad daylight !
The aim is to assassinate and get away, but get the message through pretty quickly. It's not at all the same kind of stealth as in Hitman, so if you're really into that kind of stealth, you won't find it in AC. Still, I do agree that at times Altaïr and Ezio are far too flamboyant and stylish, but that's Ubisoft. Still, AC 1 was a nice game despite that, I'm sure AC 2 will be too.