I think that they've never managed to top TXF later in their career. BNW is great and I consider AMOLAD to be a serious contender here (btw, I think that AMOLAD kiiiinda does sound like TXF pt. 2, in a way), but I believe that TXF was a lightning in a bottle. They already had many bluebrints from the 80s they could have replicated, they had a formula that worked well, but they decided to do something else - and I do respect such an attitude. I'm not saying it's a perfect record, but it certainly is unique.
Perhaps the production isn't the best, maybe the album should have been shorter (was including The Unbeliever necessary? I doubt that...), but it is what it is. Yes, the songs are repetitive - but that's a criticism that could be raised about any album released after FotD. Personally, I definitely like the vibe of TXF. It's not for everyone and it might be described as depressing, but it took some balls to release an album like TXF, especially if your biggest hits were songs such as Run to the Hills, 2 Minutes to Midnight and Wasted Years.
I've never had any problems with Blaze's vocals. While Bruce's version of Sign of the Cross is one of the highlights of Rock in Rio, the rest of the songs wouldn't suit his voice. I don't think that the 1999 performance of Man on the Edge had the pessimistic atmosphere of the original. And while the Death on the Road version of Lord of the Flies was interesting, I can only repeat what I said about MotE.
It's not their best album, but it's one of their boldest, most original releases. And considering the band's love for long, moody intros and outros that can be heard on the records released post-TXF, I dare to say it was a turning point in their discography. For better or worse.
I didn't really like it at first, it takes some time to appreciate it, but it's a rewarding material, pretty much the definition of a grower. I'm glad to see that after some time more and more people start liking it. It actually happens to many albums in the world of heavy metal, but TXF is the clearest example of the phenomenon.