There's one thing that's not easy to do in IPv6: merge multiple servers providing one service each into one master address providing all of those services publicly. Instead of being able to do a simple NAT from the public master address based on port, now we get to expose all of the backend servers directly and individually. That means more DNS lookups and more delay client side.
Is there a way to do this, without proxies running on the public server, with IPv6??