Personally no, I don’t think so. I know this isn’t really what the question is asking but I have to say in terms of Vader coming back? I really feel the ST missed the mark on not having Anakin just once speaking with Kylo. But as for an impostor or even Vader coming back? I’d say no. To me, Vader’s story had been told in the previous six movies and while they were decanonized? We got so much in various novels, comics, the radio dramas and more. Having more Vader to me just would come across as tacky and too focused on fan-appeasement when with the ST I want something different, fanservice is fine but I want it to be used in ways that enhance the story instead of reminding me I could be watching another film.