And we don’t know what kind of punishment he got between movies for thinking like that.
I like the effect. It shows Vader dropping his guard and proving to the Emperor that Vader has become a dangerous liability and not just old and weak. You also get a sense of his evil courtiers and Vader being part of constantly bickering clique only held together by Palpatine’s bloated ego. Any one of them could be a Snoke but he has them all tethered and resentful. Such is politics 😆