Comically IPv6 now has almost all the neat stuff IPX did. There probably is an argument for more datagram centric networking these days as the underlying services are generally much faster and more reliable and there is so much more session tracking going on at higher application layers anyway.
twinax I think is used more like a balanced line with shielding. Twisted pair is preferred because it is cheaper, but for short stuff like SATA the cost difference is so low it might as well be used
I remember removing the IPX route entries from our Cat65 MSFC back in 2006 and from the ATM/Framerelay WAN Equipment. Wasn't very popular with the customers.
I also remember the first IPv6 Workshop on W2k SP3 back in 2002. Not that long ago.