Sauron's Super Army?

[Inziladun]

Originally Posted by Mornorngûr

However I still think that there was some possibility of corrupting Ar-Pharazon with a ring of power that belonged to the Dwarves, if he had recovered any at this point?.

There's no concrete information as to exactly what was the manner of disposition of the Seven (or Nine, of course), nor do we know how quickly Sauron recovered the three that survived. I wouldn't think though, that there had been sufficient time for him to have recovered any before the Downfall of Númenor, for him to have had enough time to satisfactorily observe their effects on the wearers, and to have brought about their recovery. After all, it wasn't until the lifetime of Thorin Oakenshield's father Thráin in the Third Age that that ring, spoken of by Thráin as "the last of the Seven" was taken back.

I think there are other reasons too that would have held Sauron back from trying to turn a Númenórean king.
For one thing, it really wasn't necessary to do that to Ar-Pharazôn. He was for all practical purposes a puppet ruler when Sauron was in Númenor, and when Sauron already had that sort of control, using one of the precious Rings would have been overkill.

More importantly though, Sauron might not have wanted the masses in Númenor seeing what the end product of the wraith-process really entailed. It might have frightened them enough to have turned them off their path in which they strove for immortality. My thought of that is that the state of the Nazgûl was actually what immortality was for a mortal. They could not get new life, only a lengthening of what they had already, and seeing that displayed openly in the figure of their king might have led to some serious soul-searching which could have derailed Sauron's plans.