I also still don't see what you mean about dbus, the Linux kernel itself doesn't specify a wire format for arbitrary messages, and doesn't specify all the things that you need to get the complete functionality of a message bus. Maybe you could get that with another operating system that is based around message passing but Linux is not that. The methods you describe could technically be done without a daemon, but they still require a lot of additional code to set up a bunch of files and sockets and enforce ordering, security, etc, which could also contain bugs. You could tell the applications to implement all that themselves or you could put it all in a daemon which is mostly what dbus does anyway, and by doing it in one daemon it totally eliminates a certain class of race conditions and synchronization issues. Again please refer to the comments by the dbus developer that I showed, this conversation is not new and already happened years ago. If you want to store ASN.1 or S-expressions in a d-bus message you can do that pretty easily. And if you really believe that your solution could work then I would encourage you to develop a dbus implementation that works like you describe and then test to see if it works exactly the same and doesn't break existing setups. But I don't think this would really work, you wouldn't really be saving many lines of code, and in particular multicast and service activation would be pretty hard to do in the way dbus does it without a central message bus.
If you don't agree with GNOME or KDE's policies and you want to implement your own IPC then that's great, I support you doing what you need to do, however they chose dbus a long time ago, and currently it's looking like X is not the right tool for them anymore, so you may just have to accept your differences and move on.
