As far as I know, the shockwave ring that was taken to 'enhance' all of the planetary explosions, was meant as an homage to one of the old StarTrek movies. I also think it's a bit pointless to talk about realism when referring to a StarWars movie. I'm pretty sure that a 'scientifically correct' exploding planet would look neither like the old nor the new version. I just like the old explosions better - it's as simple as that. Long live unrealism!
