The norm seems to be that Jedi continue to, or tend to, manifest as they appeared when they died. I’m sure this is not a requirement, but a convention. And one has to venture into alternate versions of the films to break this norm (04SE or subsequent).

I’d rather they had filmed Hayden doing something substanative than used CGI to recreate Shaw. However, since they didn’t and using CGI is necessary to get either of them, I think Shaw fits better. Otherwise it’s three old men and Hayden. Shaw is the only Anakin ghost for me in ROTJ, and so it would seem to fit naturally for TROS.

That being said, I’m content with Hayden’s Anakin as he currently appears in jonh’s clip if Shaw doesn’t quite pan out.