It is curious to me that after decades of scurrilous activity in the White House, the media suddenly felt compelled to report it when it was Nixon. You will notice how they changed course completely when Clinton was in power.
The proper thing for Felt to do was to go to the Grand Jury. If he felt the Grand Jury had been compromised, then it was his responsibility to rresign and hold a public press conference detailing the reasons for his resignation. Instead, he found a willing reporter to whom he could feed information while maintaining his goverment paycheck.
Felt's actions were intended to bring down a president. Nixon's actions were to help subordinates. I think it conceivable that Nixon could not have seen the consequences of his actions, while Felt most certainly knew that Nixon could be impeached, and that the succeeding president would be weakened.