Hello,
You need to find evidence to prove your impact on your field and your influence on your peer researchers. Recommendation letters alone are not enough. For the importance of your work, you need to find some actual data to show the importance and the benefits of your work.
I have helped lots of people here with their RFEs. Please search "fsa2000" in this forum and you will see many successful examples. If you have further questions, you may email me at: fsa2000@gmail.com and I will help you analyze your case in more detail. Good luck to you.