In Texas we have a Board of Pardons and Paroles that consists of seven members appointed byt he Governor and approved by the Texas Senate. In addition there are about 15 commissioners that operate in groups of three distributed among geographic regions of Texas that actually hear petitions and process paperwork. The Governor cannot grant a parole wihout the recommendation of the Board.

I don't know how it operates in your states, but they all seem to have the same criteria in common and are largely subjective. You can't predict how someone will act in the future and you don't know if someone is authentically remorseful.