When I was playing GTA San Andreas I thought it would be better if the time cycle was slower. Then, I got GTA IV, which effectively doubled the time cycle.
And you know what? The overall feeling was even worse!
So, after GTA IV I played Oblivion and I felt the day/night cycle was just right.
Because it's not about realism, but more about the feeling of living a journey. In both GTA SA and TES IV I could start a mission in the morning, and be done by the game's evening. It was really satisfying.
Instead, you could complete almost any GTA IV mission started in the morning ...at noon, if you were superslow. Most of the times I didn't notice a mayor shift from day to night in-missions.
So, if they were to add a slower clock to Skyrim, I hope it's just a bit slower than that of Oblivion.