You're implying I approve of most of the EU. I don't. However, comparing an entire story to a useless change in background info, and not particularly straining background info at that, is a stupid as renaming Korriban Moraband.
And how would that be any different if the pre-Banite Sith did the same, the cruch of your thinking is the title Darth should be something only Banite Sith use, because Bane just pulled that title out of nowhere?
We don't even need Sith tbh, most people just saw Vader as a Fallen Jedi Knight.
__________________ "Vader's pulse and breathing were machine-regulated, so they could not quicken; but something in his chest became more electric around his meetings with the Emperor; he could not say how. A feeling of fullness, of power, of dark and demon mastery -- of secret lusts, unrestrained passion, wild submission -- all these things were in Vader's heart as he neared his Emperor. These things and more."