Hello Xwheelguy, thank you for your advise. Yes, I will probably place an ER for promote body (and for other improvements too), It will take me some weeks though. I have been learning NX for a few months and we have recently started to use it in the company, we had a "trial" period and now we have just received the final licenses so I think we are able to place ER now. I think I still need to learn more about the command before that, for example I wasn't using "unite" after "promote" and this took me a lot of unnecesary repeated hole features that I don't need now (I still think that hole feature should let you go through more than one body, though). I want to be sure that what I am asking for, is really needed and that is the best solution I can find, and also a realistic request. Posting here and reading other people post helps me a lot with that.
Promote body is in my oppinion a very good, and powerful command (Is a better way to do the job than the one for other softwares I have seen, and better thank wave linking because os geometric duplication, part list...) but I think it need some improvements. For the kind of products we design is not useful but mandatory to use this promote body, its because of that that I was so worried about it.
Now, I think the way "unite" command works for promoted body can be improved in some ways, for example when you select a component in the assembly navigator if that component have been promoted and united to other you don't see this component selected in the graphic window and I think it would be good. I have also seen some extrange behaviors (promoted bodies I can't see when editing a feature applied to this bodies...) but they don't always happen so I need to learn more about them.