Sauron and Saruman?

[lathspell]

If they are comparable, then we can assume that the natural behavior of good people claiming the ring would be to lose the ring, in which case Sauron could get it back quite easily.

I never said anything about all the 'good' guys. I compared those that had great power of mind, that's quite another thing than comparing them with all other good ones.

No. No one "needs" the ring. If they think they do, then they've been corrupted. No, the wise know that absolutely no one should use it, and if they're truly wise they know that the correct path is the one they chose in LOTR, to destroy the ring.

Oh yes, ofcourse the wisest path was to destroy the Ring as has been done in LotR. yet the point of this discussion is, would Sauron ever be great enough to be Dark Lord. You say that no one needs the Ring. Of course Sauron needed the Ring, but besides this... if Sauron was to be overthrown the person who had to do this would be needing the Ring, otherwise the commotion around the Ring wouldn't be so great. They would just overpower Sauron and destroy the Ring afterwards.
But the thing is that Sauron was too powerful to be overthrown except by using the Ring. Therefore the Ring was needed, and the Ring didn't have to have influenced the one to overthrow the Dark Lord.

Sauron would have been enslaved not annihilated, and the Dark Tower would not have been destroyed but occupied.

Exactly, and this time the Dark Lord would have the Ring and be corrupted. But would the Ring then overpower his new Wielder. No, I think not, otherwise that new Wielder couldn't have overthrown Sauron in the first place for he would have no power over the Ring, and therefore not be able to use it against Sauron.
So, Sauron would still exist and the Dark Tower would be inhabited, but by a new Dark Lord and that would be the one to rule the Second Darkness.