Inspired by @Luftwaffe , would you be ok with a US ambassador to a country being a citizen of said country as well as a US one?
It would be too limiting. Good ambassadors are hard to find.
Sure, why not. It would make things more convenient for them.
How would you know which country they are actually working for?
Could help relations
Nope. The man
Depends what country.
No, it seems like a conflict of interest.