It's going to have to be something pretty special for me to buy it.
Thinking about it now, I didn't buy the Arena, or the Naboo sets before it, mostly because they work so poorly as diorama/display pieces. They just look cheap to me. That opinion goes all the way back to the vintage DS. I liked it and played with it, but once I hit a point in time where I liked to just set my toys up in scenes, the SW line never did very well.
GI Joe, though, had great playsets that doubled as dioramas. I had the Flagg, the Joe HQ, the TerrorDrome, and they all felt like fully realized locations and not just a mishmash of gimicks that vaguely resemble a recognizable location.
So I don't know, I'm figuring I'll pass on the Mustafar set, unless it's something really special looking or can double as a diorama set.