To me, creativity is not about novelty, it's about making good art. That can include novelty, but it doesn't necessarily need to.
That's an interesting way of looking at it, though I'm not sure I can agree with it. I suppose it just comes down to how you define the word 'create', so maybe this is just a pointless semantic disagreement, but I tend to think that creativity has more to do with originality than quality.
Look beyond art for a moment and think about creativity in a wider scope. Think about math, for instance. In mathematics, efficient problem-solving might involve using a calculator or applying a formula. Creative problem-solving, on the other hand, is when you don't have a calculator and you don't know the formula, so you have to figure it out on your own. And it might not go well. Maybe you will end up with the wrong answer. Or maybe you'll get the answer right, but your method will involve ten times as many steps as the most efficient formula. In that case, the formula is probably a much better way of solving the problem. But there's nothing creative about that neat little formula. The piece of scratch paper with bizarre combinations of numbers and symbols frantically scribbled all over it? That's creative.
I don't 100% disagree with this, but I think there's a fundamental difference between the scenario you're describing and artistic creativity. If you just plug numbers into a given formula, this is not very creative because you didn't create anything. But when you write a song, you did create something. Even if the song is in a similar style to a song you already wrote, so long as it is a fundamentally different song, it is creative. This is definitely true of
Death Magnetic. Yes, that album is stylistically at least a cousin of
...And Justice For All: it features long, rhythm-centric metal songs, often with multiple musical motifs. And at times it uses a song structure similar to one from AJFA—The Day That Never Comes and One, for example. But it doesn't rip riffs or melodies, and it doesn't rely too heavily on filling in the blanks from AJFA song structures. To say that DM is equivalent to a mathematics student plugging numbers into a given formula is to sell the work that Metallica did on DM short, I think.
I know a lot of music fans, and especially prog fans, love novelty. Slight tangent: I've started saying that you can categorize prog fans into those who follow the Steven Wilson school of thought and those who follow the Neal Morse school of thought—novelty of output vs. sheer quality of output. I know that the Steven Wilson types love novelty, and novelty can be a good thing, but I brought up what I said about
St. Anger partially as a response to the overemphasis on novelty to which that type of thinking can lead. Novelty can be all well and good, but novelty cannot be your standard of quality, because novelty is not necessarily a good thing. When Yoko Ono screams atonally and incoherently into a microphone for several minutes on end, that is novel. Nothing like that has been heard in popular music before. But it's still bad music. And it's not creative, because it doesn't create anything that anyone could reasonably call valuable.
I'm not saying that
St. Anger is as non-musical as incoherent screaming, but the incoherent screaming is an extreme to prove a point. Everything novel about
St. Anger is something that reduces its quality as music. Mid-tempo metal without guitar solos had been done before 2003. The novel thing about
St. Anger is basically that it has awful production, particularly on the snare drum. That doesn't make it good, and it's not creative. It doesn't create anything of artistic value. There's pretty much nothing novel about
Death Magnetic, stylistically, but I say it's more creative than
St. Anger because in making it, Metallica created some good songs—better songs, IMO, than can be found on
St. Anger. And the only thing
St. Anger created that
Death Magnetic did not was a bad-sounding snare drum.
So I'd say that novelty can be a part of creativity. Something like
Images and Words is pretty creative, not just because Dream Theater created some very good music, but also because they created a style of music that hadn't really been heard before. But the latter act of creation actually was the creation of something that a reasonable person could find potentially to be of artistic merit. If I drop a spoon in a garbage disposal, turn it on, record the sound, play it back on loop for 70 minutes and sell that as an album, it might be a novel album, but it's not creative at all, because no reasonable person would say that I created something of value right there. And that would be less creative than
A Dramatic Turn of Events, even though
A Dramatic Turn of Events is not that novel due to its strong stylistic similarities to
Images and Words. But because of that novelty that IAW had, it would be more creative than ADTOE. Again, this is sort of an extreme to prove a point, but I think this is the best way to give an idea of the way I think that novelty plays a role in creativity but cannot be considered to be the whole thing. Your mileage may vary, though.
4. Kirk. Rhythm Ok. Awful lead playing. Tone deaf singer. Although surprisingly good at gang vocals. Probably had tips from Hetfield.
His rhythm playing ain't that good either, IMO. Isn't Het suspected/known to do most of the rhythm playing on their studio stuff? There's probably a reason for that. And these days, Kirk has a tendency just not to play the songs right—for no good reason. I agree with your ranking because of that: at least Lars tries to play the songs right and usually does so well enough.
And if you want to say that Kirk had some good solos back in the 80s and that therefore his ceiling of talent is higher than Lars, I would reply that Lars did some good drumming back on AJFA in particular. But neither of them is anywhere near the elite level at their particular instrument, and Lars (though he did get lazy) did not get as lazy as Kirk did.