Do the ops types include people like me who worry that every time a NIC has to be replaced it's going to require changes to DNS, ACLs and anything else that's keyed on IP address?

Mmm, I don't know. I'm the kind of ops type that also reads RFCs and understand the importance of respecting standards. From an operational standpoint, it pays off in the long run. I would never configure a server or router with an IPv6 address that includes some part of the BIA, but I try to respect standards too, and even the current standard could be respected although its clumsiness definitely makes modified EUI-64 desirable. Michel.