回複：Is my case strong enough?

Weakness with your case.

1. Low impact journal papers
2. Extremely low cited papers
3. For patents, it looks good. But it really depends on the quality of your work. I assume it is not so significant, otherwise you would have papers on high-ranking journals. Having patents does not indicate your work is of national interest. If the owner of the patent is a profit-driven orgnization, having them actually against the national interest to some extent because the public would not have the access to your discoveries. In addition, patents, by defination, does not represent the merit of your job. Actually, most of the patents are crap, such as new cap for a bottle of water, according to the INS officer's point of view.
4. Having almost all the rec letters from one place is very negative sign to the officer. They tend not to believe the credibility of the letters.

Good luck.