Non-English languages: This is the only one that has any urgency at all. China really wants .中国 in addition to .CN, and a lot of other countries with non-Roman writing would also like localized domains.
ICANN has a separate process for non-ASCII TLDs, so I'll ignore them for now.
In sum, neither of the two classic arguments for new domains, competition and directories, have worked in the past decade, and there's no reason to think they will in the future. Other than support for non-English languages, all of the other rationales strike me as wishful thinking, not business models. So I look forward to .中国 and its ilk, but other than that, they're all going to fail, very expensively.