This is the feeling I get as well. The vibe I get off Symphony X these days is that they have turned that proverbial corner from "writing complex, challenging music for themselves" to "writing simple, churn-it-out music that appeals to a wider fan base." To some degree it is hard to blame them: this is a band that likely spent the majority of their career making about enough money to eat and drive to the next gig. If you've put out a bunch of truly great albums, and one band defining (perhaps genre defining) epic, and then someone told you "ya know, if you just bang out some heavy guitar riffs and dumb it down, you'll make a lot more money, have a lot more fans, and not have to work nearly as hard to write and perform the music," that would represent a serious temptation.
I'd love to think that the reason for the time between albums is because they are locked away somewhere working out orchestral arrangements and brilliant, innovative, conceptual music, but I just don't think that is the case. I would put my money on them taking it nice and easy, not paying too much mind to the writing process, and ultimately slapping together a mediocre metal album with riffs left over from PL in that ruinous process of writing songs via guitar riffs and progressions with everything else simply written afterwards to fill out the sound.
That's the vibe I get from this band at this point. I hope I'm wrong, but I'm pretty confident in my assessment.
Oh please...