Thought I would toss this in here for a bit of size and style perspective, and fun.
These are some of my normal "daily" watches. Which I consider the Watch to be a "daily" style of watch simply due to its functionality.
This is a 42mm SS Watch
This first thing you should notice is that the 42mm is still small compared to many watches on the market, and none of these really fit in the "really large" category. (Well, maybe the Welder)
The second thing is that the Watch is incredibly seek/clean/boring/sterile/etc. This is obviously a personal style issue, but this is where I see the "cases" for Watch going.
With a traditional watch that only tells time, you get unlimited choices for personal style. Which is exactly the point of traditional watches.
There is only one style for the watch(not counting bands), but it's the ONLY choice with its functionality.
So, I see cases being more about personalization and personal style than being about "protection"