[susan53]

It depends on the surrounding context - as you've stated it it sounds ridiculous - why would anyone promote someone like that. but add a bit more information and maybe...

He's the boss's son, so we don't have much choice. But everybody knows that although we've decided to promote him, he always arrives late and never does any work. So I doubt if he'll get much respect.

And the same is true for your question regarding "nevertheless". Words never exist in isolation - only in combination with others. So you can never decide on something like level of formality without a full context.