Add security features later ...
The Internet was designed for a very specific kind of robustness - that communication between a modest number of trusted systems could be maintained in the event of a significant proportion of them being blown up. DNS fits in this system just fine.
The Internet very specifically wasn't designed to deal with untrusted systems and it certainly wasn't designed to deal handily with huge numbers of potential diverse routes operated by private organisations with commercial arrangements for carrying each others traffic under narrowly-defined circumstances. Unsurprisingly, neither was DNS.
Adding security to DNS is going to change the world in much the same way that getting a new wardrobe for Sarah Palin did.