The trailer looks great, but I know better than to trust trailers at this stage.
Skyrim is popular because of its modding capabilities. I would have never touched it after the first 60 hours if it didn't have a great modding community.
If you want a similar cow to milk, you have to be prepared to invest into creating good modding tools.
Avowed was originally pitched as Obsidian's take on Skyrim (www.rockpapershotgun.com)