It has occurred to me that Petrucci has taken the lion's share of lyric writing duties...
If you look in the credits of the albums, it wasn't always that way. Images and Words had a good mix of writers. So did Awake, and Falling Into Infinity. When Jordan joined, they lost a songwriter behind the keys (both Kevin and Derek wrote), and afterwards James and John Myung pretty much fell into the backdrop (there are occasional contributions from James, but almost none from Myung). It was a Petrucci/Portnoy show for awhile, and then Portnoy left, and Mangini entered (also, not a songwriter).
The last two albums are almost all Petrucci on the pen. Honestly, Petrucci has always been one of the better lyricist in the band at any given time, but I sure would like to hear them mix it up on the next album. Does anyone else want to hear more songs written by James? Another Myung tune? Maybe even a Rudess or Mangini tune? I would enjoy that. Petrucci has writen so many songs I really adore, but to be honest it'd be more interesting to see some other contributors.