You don't know that. Originally, no one was supposed to be appearing from TNG. Now we have Riker, Data, and who knows who else...
Just because they started in one direction, doesn't mean that things don't change along the way. CBS could've came in and redirected the show. Who knows until it comes out?
We don't KNOW for certain those characters will appear. Second, even if they do appear, it may not be in a recurring capacity. Third, just because they're on the show doesn't automatically make it TNG 2.0, a reunion show, or whatever you want to call it.
It's been established that the show is about Picard dealing with a pretty traumatic incident in his life. One would fully expect individuals who were close to him to appear. Having Riker pop up doesn't mean he's automatically Number One and they're suddenly both on the Enterprise again.
There's way too much closed minded thinking on this board. "What? A TNG character might appear? Well fuck that shit! I was promised a new show, but now I have concluded that it will suck beyond recognition!"