lulz
Dude, Huke himself has said that BRS is not Miku. There isn't an argument to be had here. You also just contradicted yourself.
Black Rock Shooter's character was driven and an inspiration of Miku. She is an original character, but the DARK SIDE of Miku.
Just because Yue (from Negima) was inspired by, looks almost exactly alike, and has similar mannerisms as Patchy (from Touhou) doesn't mean they're the same person, does it? How can someone be an original character, but still be the same? Is Dark Samus the same as Samus? You're not making any sense.
BRS was
INSPIRED by Miku, but is not the same person. The anime even sets this in stone. BRS's normal form is your average Japanese high-schooler.