I've never seen any cogent justification for the claim that the songs on the second half are any weaker on average than those from the first half outside of lyrics. It's like people think "Oh, a half-concept album from 1989 from a band considered to be a pioneer in early power and neoclassical metal, that was somewhat ahead of its time, but obviously not being a full concept album deducts innovation points, therefore I can repurpose my personal experience of ADHD-borne boredom into a facade of objective judgment with ease, how convenient". I mean, these people can't be bothered to talk about weak B-sides on more than just the same few albums over and over, so it's not like it's a universal position of boredom. Instead, it's a form of virtue signalling that is very easy for the in-crowd to latch onto. People like that love to take objective statements describing art and fashion it into an opinion. It's similar to people that by and large hate anime go on and on about how amazing Neon Genesis Evangelion and/or Miyazaki films are because their creators openly brag about subverting tropes and/or hating the usual anime crowds, which provides a convenient springboard for any professional consumer to jump from.
I mean, what, do these lyrics really make the song for you?
And every night
You'll feel my bite
You won't be scarred
So be prepared
To feel the pain
Your life I drain
And then we'll be
Baptized in blood
I am the prince of darkness
Bow before me
Fall, succumb to my trance
And be mine for eternity
Time, centuries have come and gone
But still I remain
Black, yes, I am the dark
That puts the light to shame
Like, they're not *terrible* but they're certainly not any kind of good. They're actually more embarrassing than I thought, and make me grateful for my inability to comprehend human speech in real-time. If that was the only song about vampirism, no one would give a shit about the lyrics. So the lyrics have little to nothing to do with why people pretend the first half is that much better, it's just a convenient excuse to talk about music for the sake of talking.