Toxsci said:I do not think it is possible to defend without a strong letter from the advisor. While independent scientists can talk about the importance of research, it is the advisor who has to state the importantance of the candidate in his projects along with some support from the research department. As USCIS has mentioned in the RFE that the advisor has several projects, I think they need the advisor's strong recommendation about the critical role of NIWGC2005 in his research activities (information on how difficult it is to replace NIWGC2005 would also help)
In my opinion, if only somebody within your company can say that you are so important for a project and not in the same way some independent scientists I think you will have quite some problems to convince USCIS that your work is of national interest. If you want to fit in the NIW category an independent scientists should not only be able to talk about the importance of your research but also about your importance for the company in terms of national interest. Otherwise I would highly recommend to go for OR instead of NIW.