If I were making recommendations about the AFi body, I would strengthen the handle and connection to the camera (all power flows through the handle to the camera body unless you have an extra battery on the back). I was having power problems on a body that was replaced under warranty by Sinar, though I'm not sure that this was the source of the problem.
I would make the on/off switch a bit larger with more decisive click-stops.
It's great that you can use two batteries, especially with the 12 back, but you have to keep an eye on both the Leaf back's screen AND the camera body's battery indicator. When you're working fast, outside the studio and in volume this is hard to do. All of a sudden something doesn't work too well and you realize a battery needs to be replaced. If it's the battery on the back, and the camera body battery is still strong, all you have to do is slip off the battery on the back and the other one in the body takes over.
Those are all of my comments. It's a great camera to work with and the quality of the Leaf back is so good that I can't imagine an improvement in image quality (what would it look like? MORE detail? BETTER dynamic range? I can shoot straight into the sun and hold shadow detail along with a pleasing sky!), and it works lovely tethered in C1 when I have the ability to use it that way. Where there is a wifi network, the Capture Remote is great on the iPhone. Even at high ISO for places where I need it, and I try hard not to need it, it looks good. I have no trouble with the screen, I can read the histogram in full sunlight and check focus if I must - love the tilt-up screen and rotating back - and would not want to trade for the Credo. All I want is for everything to keep working forever - this is a a great tool with lifetime potential. Like a good film camera used to be (I used the Rollei SL-66 and then the 66SE from 1971 to about 2001 and I still miss the tilt and built-in bellows).