No intention to throw any more unnecessary oil into these flames, but I'm very tempted to give my two cents... So tempted that I actually can't help it, heh.
...sorry, this horse has been beaten to death already.
I agree with most comments above, actually; both those who state that Blaze did well and those who consider Blaze as wrong man for the job to begin with.
Blaze was technically very lacking during those days and he has mentioned that Maiden days taught him a lot when it comes to using his voice and how to deliver different aspects of it. Blaze has never been the most versatile singer around, but you can say that he has definitely improved a lot since those days and done pretty impressive job with his more or less limited range.
One of the biggest problems with his Maiden recordings was the range where he could give a lot of "narrative" output with his delivery and really step up with his performance was rather limited; he does a very good job with most of The X-Factor tunes that are pretty moody to begin with and although a bit monotonous, his delivery with some VXI gems such as Futureal, The Clansman and Como Estais Amigos isn't bad either, but with most of the other songs his performance does fall a bit flat, if not completely bad, due to his technical inabilities with delivering some of the notes and "illustrating" the lyrics at the same time - one of the things Bruce is excellent at, probably one of the best there is. As said, it fits the The X-Factor well enough and with VXI he definitely sounds a tad bit more comfortable overall, but the lackluster production and the material that would benefit from a bit more versatile approach with delivering the lyrics does not help too much. It could have been improved with downtuning and heavier approach with the to a certain extent, especially live, but there were also some lack of technical abilities at the time that seriously hindered some of the performances.
So, I take the middle-ground with agreeing that Blaze wasn't quite capable when it comes to delivering songs and lyrics written in signature Maiden style. Then again, the approach to the songwriting and live performances didn't really make Blaze's job any easier and undoubtedly some actual producer and one or two more comforable setlist choices would have made... um, if not huge, at least notable difference and given a bit more interesting stuff for us to dig from those days. It would not have made Blaze to overcome all the challenges and difficulties overnight, but it would have definitely improved the general technical quality of their efforts in the long run. Whether that would have been enough for them to give that line-up one more shot with a third album is highly debatable. I dare say that maybe not, but it would have made the "pro-Blaze" camp maybe one or two steps bigger at the time.
Personally, I really enjoy most of the studio recordings from Blaze days and there are a couple of songs where he really gives an impressive performance that fits the song, but with stuff like The Clansman and Sign of the Cross, the way Bruce manages to make lyrics come alive and illustrate the story with his delivery gives you a very strong contrast, whether you like Blaze's voice and work or not (I do, but that's not the point).