Most home routers already act as an inbound firewall. Regarding "back to square 1" - the aim of IPv6 is not to expose thousands of poorly secured LAN devices to the public net - it's to restore the point-to-point nature of the internet. I would still expect most LANs to be firewalled when IPv6 is adopted

Just to expand on that, with IP6, it would make sense to simply give every router, DSL "modem" etc a [ed: theoretically, publicly] routable ipv6 subnet. This makes (in theory) everything easier: the firewall can simply block/allow -- no need for long chains of NAT-rules. It might make networks marginally more transparent -- but it really means very little in terms of security. Nor really for privacy.

Addressable != routable.

Think of a doorman for a luxury building or a gated community. The people living inside have publicly available addresses, but knowing the addreses doesn't mean that the doorman will automatically let you through to go visit.

You will still need a router at home, and it can still filter any packets coming in/going out, even if the connected devices have globally accesible addresses. So, there should not be a huge problem.