Hello there. I'm new here (although a long time lurker) and I thought now would a good time to register since I think I might have something to contribute to this topic.
I must say I agree that the video that Adywan posted looks like a great fit for the shield generator explosion. But I also think I figured out why he won't be using it in ESB:R.
First of all, I failed to find any version of the video in higher quality than the 480p one on Facebook. I did find a HD clip from a show on the Discovery Channel that featured this video but even they used the low quality version, leading me to believe that a higher quality version simply isn't availible online.
I also discovered that the video was made by a US weapons contractor in Iraq who as a test exploded 100 ton of ammunition in Iraq back in 2006. It’s needless for me to say that it's pretty unlikely that Adywan would be able to get permission from a US weapons contractor to use footage of one of their weapons tests in a Star Wars fan edit…
Not only that but since the video was made in 2006 we can't even be certain that it was recorded or stored in an HD format, since they weren't as widespread back then.
Ronster, pyrotechnics are an option I guess. It's what they did with the generator in ROTJ and I must say I really like that effect. But you have to be extremely professional when dealing with pyrotechnics. Everything has to be set up correctly. And assuming Ady has only one model of the generator, that means he has only one chance and one take to get it right.
Also, I like the work of the guy whose demoreel you posted. Adywan, I have some links to demoreels and possible candidates as well and since I'm a bit of a compositor myself I might be able to give you a few tips as how to go about something like this, do you mind if I PM you on the subject?