I really don't understand why people make such a big deal about a video game that they think sucks. If you don't like don't play it! Just because you don't like it doesn't mean you have to tell everyone that thinks it's decent that they're wrong. Of course the game is going to be way different from the original. With what people like in a first person shooter game today, the have to change if they want to sell. I personally don't like playing a shooter game with no aiming down the sights, so I'd be more inclined to buy this game knowing that you can than I would if you couldn't. I can see that maybe you don't like the modern FPS, but they're aren't advertising to the smaller portion of the people in the country. They're marketing it towards the part of the country that loves the modernized type of FPS, where they'll actually make a decent amount of money.
You want you're original game play it, but since not many people now-a-days have played the n-64 version, they're not going to try to just refurbish an old game and sell it. They're trying to make a new game that they can sell to the new generation of gamers.