Meanwhile adding science fiction things like mobile IP.

Yeah, that one's a bit silly.

That's a solution to a problem you don't personally have, and it exists in IPv4 too.

Your cellphone company uses it - or would like to.

It's like SCTP: just because you don't use it doesn't mean there isn't a big group of people who do.

That's the adaptation layer between Ethernet and IP.

Broadcast was renamed to "all nodes multicast". ARP was renamed to Neighbor Discovery.

Slight improvements: ND isn't broadcast, but multicast based on several bits of the IP address. This allows NICs to filter most of the irrelevant ones based on multicast MAC address. And subnet broadcast addresses were removed. There's only local broadcast to your own subnet and not to someone else's subnet, since IPv4 routers found that to be a bad idea and mostly started blocking it anyway.