@LOTRIsTheSwordOfLife, here is a quote I found in one of Tolkien's letters on the nature of Sauron's evilness.
“Sauron was of course not 'evil' in origin. He was a 'spirit' corrupted by the Prime Dark Lord (the Prime sub-creative Rebel) Morgoth. He was given an opportunity of repentance, when Morgoth was overcome, but could not face the humiliation of recantation, and suing for pardon; and so his temporary turn to good and 'benevolence' ended in a greater relapse, until he became the main representative of evil in the later ages. But at the beginning of the Second Age he was still beautiful to look at, or could still assume a beautiful visible shape – and was not indeed wholly evil, not unless all reformers who want to hurry up with reconstruction and reorganization are wholly evil, even before pride and the lust to exert their will eat them up."
Something to point out is that even the wise, like Gandalf and Elrond, never consider reasoning with Sauron and attempting to change him. Instead they view him as an enemy to be destroyed. So even if Sauron was not entirely evil he was evil enough that no one hoped for his repentance. Tolkien also said that one of the themes in his work that Sauron represents is power usurped for domination. So I believe that Sauron's end goal was to dominate and truly evil. Hope this helps!