It's not useless though, and that's an important point in this conversation that seems to be repeatedly missed. You can attribute it to whoever you want - me or Mangini or Paul Stanley or any of the thousands of people that have said it - but "I like what I like". For me personally, there's very little of this "objective" stuff - complexity, song lengths, who wrote it - that make a difference in what I end to listening to on the regular. I'm not that one dimensional, and most humans aren't*. I like things with deep theory, I like things that are nothing BUT feel, I hate things with theory and I hate things that are nothing but feel. It's not about EITHER of those things for some people. This idea that it's a binary two-variable equation - one or the other - is the REAL myth.
In my opinion that's why bands like Led Zeppelin and The Beatles and Pink Floyd are still talked about; they didn't make these distinctions; you had complex symphonies, if you will (The Song Remains The Same, A Day In The Life, Echoes) alongside simple "Squeeze the lemon, baby" blues and "Love Me Do" skiffle and "Alan's Breakfast" musique concrète, and all that mattered is that one got lost in the music.
* I'm not suggesting you or anyone else IS one-dimensional; I would ask you - and be honest - did you make a CONSCIOUS decision to like what you like, or did it really happen that you liked it, you were drawn to it, and figured out why later? Is there ANYTHING musically you like/listen to that doesn't fit the set pattern?
I like many different things, even stuff like Noise and Free-Jazz hit a sweet spot for me. I don't think there's any set way that I go about music (although I try to understand why I like or dislike things). But Mangini is one of my favourite drummers (next to Marco Minnemann and Deantoni Parks), and I love reading/listening to him talk about complex ideas; I'm austitic, and I have some kind of synesthesia, when Mangini talks about shapes and movements, I get it, and it inspires me. Applying polyrhythms to odd time sigs to create a sense of metric modulation is an idea that has been on the back of my head for months too, so I'm hyped to see how he implements it for the opening of the album.
If he talked about how a song feels or grooves, it means nothing to me, like, literally nothing. You can describe movie scenes to someone, but if you tell them "yeah, the movie is sad and then it gets really emotional", it doesn't paint any picture in their head.
And yes, I agree that it's a myth that it's about "feeling vs theory", and many musicians that know a lot of theory would then say "I just play what I'm feeling at the moment", they just have the vocabulary to explain what they do (like Mangini mentioned in his post), and know how to break "rules" to create textures and effects.
As for Zeppelin, I don't like them so I can't really comment. The Beatles I'm only familiar with a couple of albums, but I know some info about them. And Pink Floyd I can write books about their music and its influence on me. But for the last two, not knowing theory wasn't an excuse to not being creative and explore ideas/concepts; sure they weren't writing in 23/16 to explore how to use prime numbers polyrhythms or something, but it was still complex music in other aspects, and it could be talked about with "academic" terms if someone wanted to.