August 2, 2008
Brett C., how the heck are ya? It's been, what, four years?
As far as the winged Balrog debate goes, the important thing to remember is that the Balrogs are fundamentally spiritual creatures, Maiar to be exact, who sided with Melkor in his rebellion against Iluvatar and the Valar. It exerts itself to take and hold physical form, and much of its essence is dissipated when that form is destroyed. Furthermore, because they sided with Melkor (a.k.a. Morgoth or the Dark Enemy), their form reflected both his darkness and their inner fire. Beyond that, though, there is no restriction on what shape they can take. Furthermore, because they have no inherent physical shape, it follows that they can alter the shape they have taken, though it undoubtedly takes significant effort to do so.
Thus, when he stepped upon the Bridge of Khazad Dum, the Balrog had no wings. Then, in a display of his power and to make himself appear more intimidating, he altered his physical form to give himself wings.
Whether or not this is a correct reading of the text of FotR, I don't know, but it is consistent with what Tolkien wrote about the nature of Balrogs in "The Silmarillion", and it manages to account for the arguments in favor of both sides.
The more interesting question is how much of their power did Balrog's put into their physical manifestations? Tolkien's writings clearly indicate that though they were created to live forever, the Ainur were of limited power, with the Valar being more powerful than the Maiar. Did the Balrogs invest so much of their power intheir physical manifestations that when they were slain they were effectively undone, much like what happened to Suaron when the Ring was destroyed, or did they hold enough of their power in reserve that they could once again assume physical form even though they were not as powerful as they once were?