Actually, it's perfect... since the song is about fans who are never satisfied with what an artist does.
I doubt it. No matter how much control Portnoy had (or didn't) over DT, you can't make 4 other guys play rotating set lists for years unless they're on board. I've seen interviews where JLB bragged about being able to remember all those lyrics; at one time, he was definitely into it.
And when Portnoy first left DT, Petrucci initially said the rotating setlists would stay. In fact, it was one of the few things he seemed sure about.
There may be plenty of good reasons for stopping, but I don't think it's just because MP is gone.