I think he actually brings something to the table but there's one reason MSNBC will never give Sirota the spot. If there's anything the MSM hates, it's populism and Sirota is an unabashed true-believer. Not.gonna.happen.
I think Shultz is a good guy but he doesn't have(or display) the raw intelligence of a Maddow or Olberman. That's not a swipe but he can't debate a Bill Kristol on foreign policy or a Stephen Moore(from WSJ editorial board) on economics.
That's where Cenk comes in because he can. My one criterion for that slot is a progressive who can discuss any issue at any time and Shultz ain't it.