As far as Norton being removed from this picture goes...well, I can understand it. I've heard the claims about the level of creative control he tries to exert on films he is in and I can understand Marvel not exactly wanting to risk that on what is bound to be a expensive ensemble picture. And considering the less than desired box office performance of Incredible Hulk, I can see them feeling that replacing Norton is a valid financial option. We will have to see how it works out.
And as far as that line of dialogue about "wanting Iron Man, not Stark", that is just Marvel leaving themselves options. RDJ plays a very bombastic Tony Stark and it might be to their benefit to not have him in every team scene. Having him be Fury's right hand man would allow for him to be a major character in the flick, without having him "drown out" Captain America...especially since Don Cheadle's Rhodey could make a damn fine SHIELD Iron Man. Likewise, one can easily imagine RDJ's Stark entering the field unasked, delivering a pithy line about consulting in the field to Sam Jackson when called on it.
Like I said, options.