Also
@MrKnickerbocker I think Portnoy is only bad at singing when he tries to do "tuff guy" vocals
He's great at harmonies, but Akerfeldt is specifying "people who all have lead singer-type voices." So, let's just hope it's not him. Personally, I think Akerfeldt is too smart to try that. He knows that he's too particular about his music to try and take on Portnoy's ego.
I see their interactions as like that one guy at the party that doesn't understand sarcasm.
PORTNOY: "Hey dude, we totally have to do something together, brotha!"
MIKAEL: "Oh, yes. We must do that."
PORTNOY: "Yeah brotha, let's do it! I think that music would be badass!"
MIKAEL: "Yes, it would certainly be something."
*Portnoy turns his head to look at shiny things because A.D.D., Mikael vanishes*
PORTNOY (to himself): "SWEET! I can't wait to make an album with Mikael!"
Later, in interviews...
MIKAEL: "Yes, we've always wanted to do something together, but it just hasn't worked out yet..."
MIKAEL'S SECRETARY: "Hey, Mikael, both you and Mike Portnoy have January 2015 to April 2015 completely free."
MIKAEL: "NO! I, uh...I have plans. Vacation. I'm going to a sunny beach. Alone."