I love this dress and it's concept. It's gorgeous. I've read all the replies and agree with most of what people are saying.
If it was me, on the back I would, leave it pretty much as is except for moving the feathers on the feathered side so that there is no strip of the goldy/cream fabric showing, I think it detracts from the fabric.
To the front, I would change the style of the skirt, to go with the flamy illumination style I would give it an asymmetrical skirt, which wraps around and continues onto a shorter train, like this maybe...
Only under the skirt bits is where you would add your gathering and extra bits of sheer fabric in the different shades throughout the dress, including goldy cream to continue on from the top part, which would essentially look the the front of the skirt you have now only more fitted and "neat" i mean "neat" in the disorganised chaos neat... I also this a 'bustle butt' would suit this dress idea/concept too, esp the flame/phoenix idea... Thing of violent shocks of fabric graduating out from under the butt feathers to pronounce it more but not make it look like a big lump... (looks like it's already got a bit of this)
(I feel like I'm being bossy and pushy here so i apologise, I'm not meaning it to sound like that I swear!)
I would not put feathers on the front, and avoid led's or lights of any kind. I would stick to reflective or glittery beads, that illuminate with light, I would, for now leave the 'collar' as i think it's stunningly simple.
If this was my dress.... I'd want who ever to see it be saying or thinking... wow, nice... at the front then BAM OMGWTF that's amazing at the back, which is where it's at atm.
Those are just 'my' suggestions, that's all they are.
Sometimes if we are too close to a project we become idea's blind and are just sick of seeing it.
I think what ever you do, once it is finished it will be amazing.