I may be one of the few that have owned the new 5th gen 1500 CC and a 4.5 gen HD CC. If I had it to do over, I would give the MC a real good look.
The 5th gen CC has a flat floor that is open under the rear bench all the way to the back of the cab. The legroom is comparable to a front seat, maybe better. With my seat in regular position my daughter was able to walk down the aisle in front of her car seat...and like someone else said I didn't have to constantly tell her to get her dang feet off the console because they wouldn't reach. I was able to neatly stow all my towing supplies except for the WDH (straps, ropes, pins, 3 different shanks w/ball mounts, etc.), a handheld air compressor, a jump pack, a few tools, a window scraper, and a windshield cover with room to spare.
The 4.5 gen CC doesn't compare. This is the one and only spot I went backwards on the upgrade. When we were moving stuff between trucks at the dealership it looked like we were being evicted and taking as many belongings as we could. I've never seen a MC in person but based on the pictures posted here...the 5th gen CC still has it beat.
Doesn't do anyone a lick of good right now, but when FCA eventually tools up the rest of the lineup to 5th gen I don't expect much need for the MC.