Warthur
They say you shouldn't judge a book by its cover, but in the case of Judas Priest's Demolition the cover art actually gives you a pretty good idea of what you're in for. Stop and look at it a second, I'm going somewhere with this.
Seems kind of... generic, doesn't it? A bit low-effort. The sort of thing where if you learned that someone put a lot of time and energy into creating it, you'd have further questions about what they spent the time on, because it sure as heck wasn't invested in giving the album much of a distinct identity. You could switch out the Judas Priest logo on it for that of any one of a hundred different metal bands and the cover would be just as apt. In short, not an instance of outright incompetence, but nothing particularly interesting. Put the album on and, hey presto, that's exactly what you are hearing.
This is the second and final Judas Priest album to feature Ripper Owens on lead vocals. Jugulator has its credits, but I'm alright with it; the main problem with that album is that whilst Ripper was trying to sound like classic Rob Halford (that's how he got the job, after all!), the band didn't seem all that interested in sounding like Judas Priest, which meant there was a clash going on. Still, at least there they had a particular style they were aiming at - a sort of doom-tinged groove metal approach with perhaps a touch of Metallica influence.
Demolition, on the other hand, is a clear step down, simply because this time the band have no particular musical vision whatsoever: they're just sort of meandering around, here trying something in a more classic Priest vein, here trying something which sounds like a progression of the Jugulator sound, here a nod to nu metal, there a godawful power ballad, and so on and so forth. Some of these songs are alright but not exceptional examples of the style in question, but others are just awful - Lost and Found vastly outstays its welcome, whilst album closer Metal Messiah mixes choruses which sound like a cheap imitation of classic Priest with verses in an unappealing nu metal style, complete with quasi-rapping from Ripper which he just isn't good at.
For his part, Ripper does alright, but he seems to be hampered by the rest of the band not particularly taking into account his style as a vocalist when writing the songs. The result is that some of the songs lend themselves well to his approach, whilst others don't, and inevitably his performance is a little hit and miss as a result. (For example, the nu metal bits on Metal Messiah are not playing to his strengths at all.) As far as everyone else goes... well, it's all competently played, it's just that it isn't more than competent. Even when they take on material which is a bit more Priest-ish, they don't sound like Priest - they sound like an utterly generic metal band, drably playing material they aren't actually that enthusiastic.
Perhaps the idea was for the album to touch on a diverse range of metal genres, but the end result is that it half-asses all the styles it attempts. Every song sounds like a drab, third-rate imitation of a style someone else has done much better, and in many cases that "someone else" is "a previous lineup of Judas Priest".
It's fashionable to rag on the Ripper years, and when they include a turkey like Demolition it isn't even wrong to do so. But it would be grossly unfair to pin all the blame for them on Ripper. This clearly isn't a case where a really hot metal album got ruined because of a crappy vocalist - this is an album where a vocalist who's good at the particular thing he does but who doesn't have the level of vocal versatility of, say, a Mike Patton is trying to do his best with instrumental backing which is utterly disposable.
Let's be real: during his time in the band, Ripper was always the junior member, with every other person in the lineup having served longer in the Priest ranks than him. You can't blame Ripper for this one unless you want to think he strolled into the band and was so influential that he made all the other members lose their goddamn minds.
The main thing I'd criticise Ripper for with respect to Demolition is his utter lack of good taste: he actually thinks this is the better of the two albums he did with the group. He is wrong. Whilst the declared aim of the album was to provide something that every Priest fan could enjoy, the end result is an album which is trying too hard to please everyone to wholly please anyone.
There will likely be a few songs on Demolition you quite enjoy - but chances are they won't be songs you love, because they're too busy compromising to really chase down a particular creative vision. And for most listeners, the good parts of Demolition will likely be balanced against some parts you seriously dislike, so taken as a whole the album averages out as being utterly mediocre.