The email itself may be insignificant when compared with the full reality of Watergate, but that’s only because it is the first and only actual smoking gun that has been uncovered.
On a scandal to scandal basis, Benghazi has the potential to far outstrip Watergate because common sense indicates that there is far more still hidden than has yet been revealed.
When the lid is finally pried completely off this festering horror, this email will be seen as the start — but only the start. So in that sense he’s right.
There is more. Sequestering witnesses using the IRS to intimidate political opponents weaving a pattern of lies about their activities refusing to enforce laws and unilaterally changing law out side the legislative process
Nixon looks like a kid in short pants
I think that influenced the response (actually lack thereof) by US forces, trying to keep the arms trafficking under wraps.
There is the greatest significance: giving aid and comfort to the enemy in time of war.
For all his failings, Richard M. Nixon didn't come close to that.