This doesn't exactly help with credibility. It's a good album, but their best? Not by a long shot.
Just to clarify again for the sake of emphasis, JR did not say this. The closest we get to a quote like this is when John Petrucci said it was "taking things to the next level" and comments to the extent ot it being a reference point for future fans. As the hype man for DT, that's kinda to be expected. JR's actual tone around DT12 looks like this:
https://www.ultimate-guitar.com/news/upcoming_releases/jordan_rudess_things_are_really_intense_in_dream_theater_land.htm"We've made our way through the album process to a good point now. We're still finishing up, I'm doing some keyboard stuff, it's intense, it's definitely a strong process."
https://www.ultimate-guitar.com/news/upcoming_releases/jordan_rudess_on_dream_theater_this_is_what_were_all_about.html"It ended up being that we all feel that this is an amazing time in Dream Theater's career. We've put together music that we feel that we can put the Dream Theater stamp of approval on. This is Dream Theater. This is what we're all about. It's a combination of all the stylistic things we love to do that we feel represent Dream Theater."
His tone is a lot different from how he speaks about DT15, which has a bit more of a spontaneous, informal quality to his excitement, at least from what I can hear.
It's more accurate than what MP said. You have the band bringing the heaviness of ToT, the songwriting style of Systematic Chaos, but also bringing back the light, airy, and ambient moments, and proggy stuff in the last two songs and also the Beautiful Agony section of ANTR.
I don't see how any of those descriptions would even mark a shift from Systematic Chaos, given that it also has its extremely heavy moments that arguably eclipse ToT in intensity, has airy and ambient moments (admittedly with a more melancholy tonality I guess) and a
lot of proggy stuff. This is the trouble with trying to describe albums with other albums, because it often forgets the kind of variation that they have within them. Honestly, MP's probably makes more sense because at least it's more evocative in regards to the actual nature of the songs.