Making peace with all neutral is way too much OP'ed. Godmode.
Why don't you make 'truce amongst rogues' an 8 level tech, in that:
Each level enables you to make a permanent peace treaty with a single planet at most <tech level> jumps from capital.
So, at level 1 you can make peace with 1 planet 1 jump away from your capital.
At level 2 you can make peace with another planet up to 2 jumps away from your capital.
At level 3 you can make peace with another planet up to 3 jumps away from your capital.
And so on until level 8.
Making peace with the pirates would only be possible at level 7 or 8, and would render you immune to pirate raids.