I noticed 6 people thought MP's the man, but other than Marla (no surprise there) nobody wanted to comment on why he should be back.
I was one of the "MP's the man" voters. I'll probably get angry responses for it, but oh well.
One reason I would like to see him come back is the fact that Portnoy wrote some of my favorite DT songs. To be more specific ACOS, The Mirror, The Glass Prison, and Finally Free. Those last three are probably my favorites on their respective albums. Another reason is just his presence, on stage and off: he has a ton of charisma on stage, and off stage I've never seen another musician maintain such a connection with the fans. I'm voting for him because of all he's done to build one of my favorite bands.
I know that Mangini is an amazing drummer technically, and I'm sure he's a great guy, but he has never really been a contributing member of a band. He's always been a hired gun, session guy, or teacher, and honestly I think he'll decide he wants to go back to that sometime in the future. I believe that's what will open the door for MP's return.
But whatever happens with the drummers, as long as JP is the guitar player I'll be a fan.