Yeah. Iron Maiden fans think that Blaze is seemingly worse singer than Bruce is so very few would like to hear Blaze again on Iron Maiden album. Vintersorg and Vortex on the other hand are both great singers (Garm is very good too) and Andreas isn't really any worse than Simen is. And because Vortex's vocals partially defined the sound of Borknagar so it's understandable that they wanted to use his vocals on that old (and new) song. That is how it was intended to be. Borknagar can pull this off, many other band wouldn't and they shouldn't try it either.
Well it's hard to argue that. Bruce is a much more powerful singer than Blaze, but I loved both albums Blaze sang on and I would love to see him back in the band I mean I love Bruce a lot more but Blaze has his own charm too. I think they should share the stage; too bad their egos would never allow that to happen. I wish Blaze would do more Maiden covers though. At least his solo work is good, unlike much of Bruce's.