The UDRP has a good legal foundation in that it is generally based on provable intellectual property rights (trademarks) being abused. Trademarks are generally commonly respected. The problem with content is that its misuse or abusiveness is often subjective and can vary from country to country. There are some forms of content that will immediately be taken down when the hoster, registrar or registry is notified but when it gets into content that may or may not be abusive, things get a lot more problematic. The danger with advocating for such a panel of judges to decide what should and should not be published on the Internet is that some of the larger gTLDs are based on the US. The First Amendment to the Constitution may have an impact. When you go down the road of approving content, you quickly end up in the Chinese situation where every website has to be approved.
With the DNS Abuse issue, there are those who are pushing a similar line to have Content Abuse included in the definition of DNS Abuse. The Intellectual Property people want abusive registrations included because mainly it would save them from having to use the UDRP and possibly lose. There are others who don't really understand the problems of DNS Abuse and want content that offends their sensibility, which may be perfectly legal, taken down. ICANN doesn't want to get into the content monitoring business because it would lose some of its legal protections and monitoring every website in the gTLDs every day and determining what is "abusive" content would be an expensive and highly complex task. The current thinking (from registries and registrars) is that DNS Abuse would be limited to malware, spam and DDoS/botnets.Those kind of problems can often be dealt with at a domain name level.
Most registrars and hosters have well written terms of service that could be used to deal with problem domain names or hosting. A Uniform Domain Name Misuse and Abuse Resolution Policy that focuses on content would be a charter for censorship.
Regards...jmcc