Unfortunately, that letter has no credibility since the author wants to remain unknown. He/she is not giving his/her name.
If someone from the higher rank in JPMC comes out and openly talks about these issues then may be something happen. But with this letter nothing will happen. Anyone can write a letter like that and submit it.
Maybe this will bring out some more whistleblowers....the whistleblowers are just what we need....there are still some honest people left in this old world.