Why were they removed in the first place?
IDs encourage shitposting, just like your palindromic post number
Except a lot of ISPs still don't support it. If you were correct on the IPv6 thing, bans would be meaningless too.
Also, if v6 users tend to be assigned some particular sized subnet, then the ID algorithm should be designed to trim the subnet portion from the address.
Clarification: Most IPv6 allocations are on a /64 subnet size. Therefore only the network prefix to that subnet should be used to calculate IDs. It would not be a bad idea to implement this on existing IDd boards like /pol/ as well. Better staying ahead of the curve than falling behind it.