The mailing list archive definitely has at least parts of this discussion. Since we did not come to a conclusion last time, the archive is however not very helpful and you are right in pointing out that we should start it all over now.
Scripts are definitely in the same category.
In the future we will also see pluggable tools and its foreseeable that we will face the same problems there at one point. This reduces the size of the core, makes it cleaner and improves maintainability of the core. Not a very useful definition either. Those plug-ins will most likely be pretty large and only useful to a subset of users. Thus they belong into a special package.