The good thing about IPv6 is that due to the large address space it's possible to make it mandatory to encode the callsign in the last 64 bits of the address. This eliminates the problem that we have in IPv4 of trying to trace back which callsign is behind an IP.
I think it basically is a good idea, but it needs to be more flexible. We would like to be able to derive the callsign from the IP, but there should be no 1:1 mapping between callsign and IP, because that would mean only a single system can be online for each callsign.
The standard should leave some bits (at least 8) available for use as "SSID" as we had in the packet days (callsign-1 callsign-2 etc), maybe also with some encoding of alphanumeric values.
Rob