Well said, and point well taken. They should be more, as you said, than "firey trolls." But Tolkien is not D&D or Sword&Sorcery... his magic is more subtle than that, even for the bad guys.I really feel like we should be looking at these more as princes of demons than fiery trolls...
were they not Ainur, after all?
A good idea and we are going to have to explain why Durin's Bane couldn't or at the very least did not speak. If we have the Balrogs constantly speaking, then we will have to explain why Durin's Bane can no longer/not want to speak.Perhaps the more evil things a Balrog does, the less noble it looks and acts? By 3019 T.A., Durin’s Bane wasn’t able to speak.
It's more about consistency. If we have Durin's Bane speaking when encountering foes, then it makes his silence against Gandalf strange.His aura of fear and weapons speak for him? Why bother to speak when you can say all you wanted by killing the guy who stands in your way?