What issues have occured with the centralized nature of the root zone and DNS as it currently stands?

Certificate authorities and private owners of TLDs impose fees while often compromising the security of SSL by issuing bad certificates or cooperating with government attempts to spy on encrypted traffic or censor undesirable content. One common mechanism of Internet censorship that has been used with increasing and alarming frequency is DNS filtering and redirection. Another area where the centralized nature of Internet names has come to a head is domain registration privacy. Additionally, the way DNS is currently centered at a handful of choke points allows for DDoS attacks like we saw in the 2016 attack on Dyn.