I would like to offer some thought about the NIW petition through my own example.
NIW 140 Received and Notice Date: 09/06
Approval Date: 10/18
Texas Service Center
Personal background:
Ph.D. in EE
Work in the area of biostatistics/bioinformatics to solve problems in genetics and proteomics at one national institute.
6 recommendation letters, 3 from NIH, 1 from IBM, 2 from two universities. (Still got 1 from industry and it still sleeps in my drawer in case of RFE). Each of the letters is at least 2 full pages in length.
Publications: 2 first-author conference papers, 1 second-author journal paper(impactor factor < 2), 2 Citations( one is self-citation)
Therefore, I would say publications and citations are not critical for NIW. The nature of your job, the place where you work, and the strength of your recommendation letters are very important.
Personal comment:
My case is a not-so-strong one compared with the brilliant records of some others. However, the stronger your case, the faster you will get approval.
Good luck to everyone.