Future nazgûl: good or evil Men?

[Inziladun]

I find it hard to sympathize with either the Nazgûl betrayed by the Nine, or the Dwarves who possessed the Seven.
Morthoron seems to overall have the right of this. The desire of power beyond one's innate abilities is never represented as a wholly positive virtue in Tolkien's world. He said as much in Letter # 131:

With the aid of Sauron's lore (the Elves) made Rings of Power ('power' is an ominous and sinister word in all these tales, except as applied to the gods).

Men seem to have wanted the Nine to gain Power for its own sake, evidenced by what they used them for: to be invisible, to see things in the shadows that were hidden from others, to increase their stature among their peers. What 'good' reason could they have had for wanting the Nine, regardless of their character before they received them? Sauron appears to have basically said, "Here are some magic rings, use them as you will, discover their powers". And so they did.
I don't think Men, however, were more vulnerable to 'avarice' then the Dwarves. It is stated that inflaming their desire for wealth was the only power exercised over the Dwarves by the Seven. Their 'immunity' to the other effects of the Rings though, was only due to their fundamental makeup and not something they were able to consciously effect.
Even the Three were not completely 'good': they too enhanced the powers of the possessor, but it seems the Elves were able to use the Three because they were somewhat protected from corruption by the unnatural power they had gained by the underlying purposes of them: preservation and healing, as stated by Gordis.
The Nine and Seven had no such redeeming qualities, and could have been nothing but what they were: instruments of Sauron to aid in his dominion of ME.
I hope I didn't miss something important from the other thread. That's a lot of posts.