That thing JP said in the interview about escapism... unintentionally probably encapsulates why I think his lyrics got so inconsistent.
If you look at a song like Voices, I doubt Petrucci actually saw hallucinations while he was trying to sleep, but there's a lot of weird catholic guilt wrapped up in there which makes it compelling. Contrast with Six Degrees, which feels more documentary in nature. Not a bad documentary, but still documentary. Note how MP's lyrics are from the perspectives of the characters and JP's are not. I've never been in a mental institution with shit backed up in the toilet and not having showered for two days, but I feel the energy in TTTSTA.
Ironically people complain about SC because of the fantasy topics, but I mostly liked JP's lyrics on that record. ITPOE is about good and evil, Forsaken about seduction, and TMOLS about love and death. I think when most people complain about the lyrics on Systematic Chaos, they're really thinking about TDEN. I will not be the one to stop them on that one I'm sorry.
Someone might say "But JP always wrote goofy weird stuff, look at a song like the Killing Hand." The Killing Hand isn't *about* a weird time travel paradox. It's about guilt and the futility of trying to change what has already happened, lest you become the very thing you wished to stop.
Another example of both dynamics in play can be seen in A Nightmare to Remember. The lyrics during the heavy parts are what happened. But during the "Peaceful Sedation" section, what is happening is only implied. The section is *about* being in a liminal state of partial consciousness.
To wrap this up, consider The Count of Tuscany. I think in retrospect it's not as bad as we all thought at the time. But the lyrics are still absurd. Contrast with the part of the Lifting Shadows book where Petrucci talks about what actually happened. It's actually super interesting. Because this weird old guy's like "yes, get in my sports car with me and let's drive out to my remote castle. Oh, here's my brother they based Hannibal Lecter on but don't mind that. Now we're going to go to my creepy basement where people died in these wine barrels we still make wine with don't worry it's not weird at all." You actually feel like you just stepped into the opening of a horror movie where you watch it and wonder why the characters didn't leave while they had a chance.
Petrucci still writes good lyrics I wish he was willing to get personal more often that's where all great art comes from.