A Fallout and Elder Scrolls theme park would be cool but I think the former would be more popular. People in general are drawn to post-apocalyptic settings. Outside Vegas, in the desert, would probably fit the theme more as they wouldn’t need to make too many changes to make it look like a wasteland even if they don’t use the New Vegas setting.
Fallout was included in Universal’s Halloween event this year so it’s definitely not outside the realm of possibility. Whether or not Microsoft wants to run such an expensive endeavor, though, is another matter entirely 😛
As for the prize, I can understand where people are coming from but it’s an opt-in contest with the prize listed up front so my philosophy is that they shouldn’t enter if they don’t like the prize. There will be other competitions that’ll suit them better /shrug