The Inherent Incompatability of Morgoth and Sauron

[Sarumian]

Originally Posted by Zigûr

More importantly, however, is that phrase "the Valar (including Melkor) having failed."
So Sauron considered Melkor to be a failure, seemingly along with or in the same way as his enemies, the Valar. In what way?

Can it be the reason of Sauron's brief repentance after the defeat of Melkor? When he found that other Valar were reluctant to take reigns in ME, could he treat that attitude as a confirmation of their failure? May be he even had a hope that taking responsibility for the affairs of ME and ordering he could deserve Eru's respect in the future?