Never watched Rebels. Just youtubed Vader in Rebels. Kind of pathetic that they did a better job invoking 1977 Vader than ROTS. Red lenses, widow’s peak, proper robes, etc.
I agree it would’ve been better to take a completely different direction in Sith, but given that they tried to make him look the same, it shouldn’t’ve been hard.
EDIT: I also dig the yellow-green lightsaber flashes al a SW.