I totally understand the need for a campus-wide firewall. The MIT network is a juicy target for botnets, and individual students are not good enough at running security on their own computers. The old approach to IP assignment was that you needed to get your IP approved and made routable by IS&T anyway, and if they detected botnet activity on your computer, they'd manually intervene and make it unroutable again. That sounds like a lot of work.
If computers end up with firewalled but publicly routable IPv6 addresses, that sounds perfect.
If they detect bad activity, they blacklist your MAC address so you can't connect. This is no different under the new scheme, and has nothing to do with NAT.
But I have my doubts. http://pilot2021.com/index.html
MIT was always going to be the last place on earth to go total IPv6
The "just" is incorrect. There are four bullets on the slide: DHCP, IPV6, private IPV4/NAT, and firewall. From the diagram it looks to me like even if you move to IPV6 (which, as others have noted, MIT has not yet rolled out, so at this point you can't), you will still be behind the firewall, so setting up a service visible to the Internet will still be more difficult than it used to be.