For this type of shooting the 1Ds2 always did well. It has a bias towards the reds, so sunsets look punchy. The 1Ds2 if exposed for highlights had a nice roll-off, and as for dark areas, who cares, they're just going to black anyway. The 1Ds2 did well in this regard, and I expect no less from a 1Ds3. These are the 1Ds2 -
For images such as those above, the 5D had problems because it would clip the sun in a very harsh way. One of the channels would blow about 1/2 to 1 stop earlier than the others there would be greenish or some other colored halo around the sun. The 1Ds2 does it too, but to a much, much lesser degree. IMO scene like this will stress test the sensors much more so -
There are parts of the snow bank that are just blown. In a small web size it's not a big deal, in print (24'x30") the loss of texture makes the image look a bit too polished (IMO). It's just a mass of white. Both pictures are the same scene; one @ ~24mm and the other @ 200mm. Trying coax much more out of those image isn't possible; and I don't like the HDR comic book look. Normally I'd shoot a scene like that with a graduated filter, but with 200/1.8 it wasn't possible. I did used a CPL to hedge the exposure.
Whether the 1Ds3 can match the detail in a 22 MP back (or come close enough) doesn't matter to me. It's about the dynamic range, how clean the ISO 50 and ISO 100 shadows are, and color fidelity (gradient quality & smoothness).