Flux shield's uses aren't extremely different. Reflecting your own spells is a rare case that pretty much solely occurs in the firestall mirror. I don't think we need an elementshifted Reflective.
A firestall deck can go into a match knowing full well it can win by reflecting spells of its own shield. That wouldn't be the case with Flux Shield. The opponent would have to rethink his strategy.
I realize that, which is why I restated it. The point is that Flux Shield is so very slightly different that it does not deserve to be made into a separate card. Reflecting your own spells/being hit by your opponent's reflected spells is an incredibly rare case, which makes Flux and Reflective very, very similar.
I'm saying it would change how a pure spell-damage deck would react. Also, who knows what other cards I got coming... 
I think it's an incredibly poor idea to design cards that require other new cards in order to be somewhat useful. Designing cards that would benefit EtG individually is probably a better use of time.
