You are forgetting that the ACS/OpenACS is much more than the Tcl scripts. It is also the underlying data model, a fact which is significantly more important in the 4.x architecture with the object model. The port to 4.x is important because it makes the system significantly more open-source friendly through its modularity. Porting 4.x *plus* moving to Python would be a huge added burden.
Remember also that we have a community of thousands of users who know and understand Tcl. Tcl isn't broken. As a language, it doesn't need to evolve. Functionality can easily be added through AOLserver/Tcl C extensions like ns_xml (which I believe contradicts your point that we don't have good XML capability in Tcl).
You're right about the idea of mindshare. Mindshare is important. But I think most developers in this community are more interested in mindshare in the field of enterprise-level web applications, and not so much in being the unknown hero of a language war.
Certainly, I'm psyched to see people developing Python support for AOLserver. I'm personally interested in web architectures. Python support in a multi-threaded environment is a great new way to build web applications correctly. But it's not so superior to Tcl (if at all) that I personally want to port all of my code to it. And if you and a series of other developers want to make this Python project happen, you're more than welcome to! We'll link to your project and I will consider it a wonderful development for the OpenACS community. But there's no reason for the core development right now to change direction so radically only because of language preference.
