It also has to be very easy to use. There are a lot of languages I won't even look at because they're not intuitive, and there's no clear reason for me to invest the time to learn them. I think developers tend to focus on "innovations" that only nerds will care about, and neglect making innovations in how easy the language is to learn, use and read. At the end of the day these features are the main factors determining whether or not a language will be adopted.