I recently posted my feelings how Dream Theater is not the same band since Mike Portnoy left. As with most teams (music & sports), when the star leaves, he is replaced. Everyone is replaceable; perhaps with the exception of Derek Jeter. The result could be positive of negative. For me, Mike Portnoy leaving DT was negative; they are just different now. They are missing something.
On the other hand, Kevin Moore the keyboardist on "Images and Words" and "Awake" (considered by many as DT's best album) suddenly left the band and his replacement Derek Sherinian lasted one studio album. Then along came Jordan Rudess, a Julliard prodigy, and an incredible player. Jordan just killed both earlier DT keyboardists, and his presence greatly improved the band. This time, a replacement in DT was definitely a positive one and Jordan's impact on "Scenes from a Memory" put DT back on the map of great progressive rock bands. And it has continued to the present. Jordan Rudess is easily the best musician in Dream Theater. He's just brilliant.
Now this may shock you. I feel that Jordan is not only rock music's best keyboardist today, but after serious thought, I have to say Jordan is a better player than the great Keith Emerson was. This opinion comes from a keyboardist (me) that said "Thank you for changing my life" when I first met Keith Emerson. I was speaking not only for myself, but for the thousands of keyboard players that feel the same way. Keith Emerson took the ignored keyboardist from behind the drummer and made them recognizable. He was the first keyboardist to be a band's frontman that wasn't a guitarist or singer. He changed the musical world for keyboardists everywhere.
Nevertheless, Jordan is the greatest player I've ever heard. However, he will never attain the legacy status Keith Emerson did. After all, Keith composed "Tarkus" and "Pirates"; enough said.
Dream Theater's addition of Jordan Rudess is without a doubt the most important change in Dream Theater's history. He's made them a better band, and better musicians, year after year. And yes, he does blow away his fellow bandmates, whether you agree with that or not.
Well, first let me say I agree with your first statement that the band is different without MP, but I don't agree with anything else there. I think they're way better now without him, no disrespect to MP because he's a great drummer. It's just that MM is a next-level player, with whom only a few can compare.
With respect to JR, I pretty much agree he's so damn good. He's the best out there now but I think it's important to caveat that players need to be considered in the context of the style in which they play. I think he is the best
proggy/prog-metal pianist out there. Also, I am not sure if you play any instruments, but I do not think it's accurate to say he blows the other band members away. If you are a guitarist and you post here, you have to know that JP is a a legendary guitarist who is going down in music history. MM is a similar story, even though he never played in such a big act for an extended period of time -- he is truly next level. JM is also an elite bassist. I think today all the instrumentalists are at the top of the food chain in their respective instruments, which is totally awesome and very rare.
On the other hand, I could see someone making the case that Kevin Moore is better because he played on better albums and had better solos. That'd be a fair argument.