Maybe, but to me, it's MP being MP and it's hard to rate him low for doing what he does. I guess I'll give a shot at my rankings:
1. Bumblefoot - easily the most impressive on this album and that could be due to me not being familiar so I didn't know what to expect, but he really shines here.
2. Sheehan - I've always enjoyed his playing, but I think he takes a back seat in the production and the music benefits from it. It's not like he's not there, he is and his playing is great, but it's not in your face and it's not disrupting the sound of the album or the other instruments. Part of me wants to put MP here, but I think that him taking the back seat is actually an advantage and he should be credited for that instead of injecting his tone all over this album.
3. Mike Portnoy - MP being MP. Nothing new here but also still does his thing and his drums are great on the album. If the complaint is that he isn't breaking boundaries, fine, that's fair, but it doesn't mean his drumming is bad. It's great and it's still better than lots of other drumming I personally listen to.
4. Derek - He shines in some spots and in others he just does nothing. Figaro's Whore is terrible. His contributions to God of the Sun could have had him higher in this ranking but between Figaro's Whore and his mouth, he goes here. He didn't live up to his own hype.
5. JSS - Eh, I think from reading others reviews, I am alone here. But he isn't bad at all, but he also doesn't bring anything to the table for me. His singing is fairly straightforward for the entire album. I think I like his softer singing better personally like in Alive, but by the time the album is coming to an end, I feel like I am happy to have an instrumental to let the other guys do their thing vs hearing more of the same from JSS. It doesn't help that the vocal melodies aren't that interesting either.