I concluded that IP addresses are messy but workable. I also concluded that the Krebs attack was IP, not domain, and mucking up the DNS does not change the equation for those attacks. But Krebs linked to Schneier https://www.schneier.com/blog/archives/2016/09/someone_is_lear.html who thinks the DNS is a target:
Verisign is the registrar for many popular top-level Internet domains, like .com and .net. If it goes down, there's a global blackout of all websites and e-mail addresses in the most common top-level domains.
China is responsible at least indirectly for the attack on Krebs which leverages insecure Chinese routers and other internet devices. Google stepped up to protect Krebs but will only protect media and other politically chosen domains. The rest of us are SOL.
The current question is whether giving up legal authority makes things worse. Undoubtedly it does. But more workarounds will be needed regardless considering Schneier's statement about taking out Verisign's domain name lookup. The biggest problem will be that everything will be messy and balkanized. You may need a special browser, or a special features will be added to every browser to do some alternative form of IP address lookup, and whoever runs that may be able to censor sites they don't like.
Facebook and Twitter and Kindle and possibly even Google would favor a more international firewall and probably give the US TLDs second-class status.