While I do really like both of his albums with Maiden, Blaze was just the wrong guy for the job, but the blame happens to fall on Steve. It should have been clear that his range was nowhere near up to the task of handling most Bruce era songs they threw at him, especially for a prolonged tour (which both tours were). It wouldn't have been as much of a problem if they'd have tuned down the songs to accommodate his lower range, but Blaze (in his old biography) and more recently Janick have both said that doing that should have been done, but obviously wasn't.
That said, I'm still a big fan of his, and much of his solo stuff (his first four, in particular) are really worth checking out. I saw him in 2011 and, big surprise, singing songs within his range makes a TON of difference. He sounded brilliant.