My thing is it would make sense that there would be an airlock of a sort attached to the entrance of Vader's chamber, due to his medical condition. You could say that the meditation pod would serve that function, but being that it is wide open with Vader helmet-less (to provide Piett and the audience a gross Vader head shot), it kind of defeats that purpose.

I would consider the "doing it because you can" to be near a frivolous change with no logical merit (not that adding something of yourself is off-limits, as one of the purposes of fan edits is to be creative and add a bit of yourself to the movie... especially considering that most of us won't have a chance at directing movies, much less big-budget ones).

One could consider the planet the DS1 orbits in ANH:R to be a DIBYC, but it also helps establish consistency with JEDI as well as help showcase the presence of the Empire as an expansive force.

Regardless of what is added or subtracted, the main considerations are:

(1) does it help the flow of the storytelling (edits, visuals, etc)
(2) does it make logical sense (the side of the Executor being darkened and the windows being brighter and bluer to match continuity with the other model shots)