Whilst I've been working on talkeuro, several issues have come to the fore. MovableType is great, but it is very focused on single author or publisher setups, at least from the point of view of template management. MT does a good job of managing actually writing new content for your site, the template management side is weaker.
Where MovableType has problems is in two key areas. The first is more generic and is about multiuser access to templates. There is no obvious way to hook something like subversion into MT so that several people working on site templates can do so and not worry about clobbering one another when saving changes. You can imagine a system where all the templates are pulled out of MT and on the filesystem, then managed via subversion. There might be hooks to do this, so that an update to subversion (or CVS) will trigger a rebuild in MT. Ideally I want to edit in my development environment, preview easily and then commit changes.
Secondly a way for MT to allow the same weblog content to appear under two sets of templates. eg www.talkeuro.com and staging.talkeuro.com would be really handy to come from the same database content. Thus allowing easy testing and bugfixing, whilst not live to the world. You can fake this, by having multiple templates and publishing to shadow directories, but it is fragile.
Another issue for me with talkeuro is multi-lingual support. Talkeuro has an english and a french version. To manage both of these I need to maintain two separate sets of templates, where ideally I'd have one template and if french use (Voyez cette section) and if english use (See this section). This is roughly how the internal localization of MT works. So as talkeuro gains languages and I want to add functionality to it, I need to hand edit each template or place each code fragment in a separate template module, which starts to get tedious.
I'd love to see these areas addressed in a future version of MT, 3.16 is a good step along the road, but more is needed to make it really scale for more complex CMS type applications.
I'm trying to get a picture of how this might look. It may be possible to write plugins for MT that would get us some of the way.
If templates are linked to files, it might be possible trigger an svn commit when edited templates are saved in MT. I'd need to check through the API and think how the interface would work if there were clashes, but it might be an option.
Is each language a separate blog? It would be possible to write a plugin that, when templates are rebuilt would look up some custom tags against a database and replace them with appropriate text, dependent on which blog the page is from. ie.
which would be replaced by the appropriate Chapter Heading for that blog.