Well, it seems that the battle is over, and I lost. :-) I'm still not really convinced because I feel that you are seeing threats that are not really there. Was consistency ever a real problem when we still had subpages? Yes, some articles contained pieces of discussion that belonged on the Talk pages, but that was usually solved in time.
I want to be clear about one thing. My argument has less to do with how user and talk pages are differentiated by the software than it does with the point of having these extra namespaces -- we want them to seem different to users, so they know they are in a different part of the site.
This could be done while using the Talk:XYZ format, and it could also be done using XYZ the (Talk) format, but I think it is important to make the conceptual distinction between disambiguation of terms, and the creation of a penumbra of wikipedia related materials which are not encyclopedia articles. If we were doing this from the beginning, I think we'd be far more willing to do it your way, but fortunately or unfortunately we are already working with live code that uses Talk:XYZ style namespaces.
Another issue I just thought about is that we've discussed at great length when originally thinking through the idea of namespaces it that we might like to at some point create a "Stable:XYZ" namespace, which will contain locked versions of wikipedia articles which have been in some special way validated by a group of experts in that field. These articles might very well include () style disambiguation, at some point we'd clearly want a stable version of "Lincoln (Nebraska)." This and this would would make using () style namespaces for the stable branch of the wikipedia "codebase" very confusing.
Yours Mark