Erik Moeller wrote
We need to make clear that a template is a fundamental intrusion into the article namespace and, like a policy, needs broad community support before being put into active use.
It's an argument. Another argument is that restricting the creation of templates is un-wiki as an approach. It says that excluding some bad ideas is more important than allowing the inclusion of some good ideas, that don't have general support in advance of being tried..
Marking templates as "proposed" is an important step towards clarifying the distinction between merely keeping a template and allowing its use.
Again, goes against 'be bold'. In general it has served WP well to let things happen, take the consequences, set up procedures, such as template deletion; and not be too scared about things that are foolish for a while. For example: a low-use and not very useful template can be removed from enough pages by anyone who is annoyed enough. A popular but silly template presumably needs tweaking to preserve the reason for popularity.
A wiki is in general a system of permissions rather than a system of restrictions. This is surely still a major asset to Wikipedia. New people constantly arrive, and I suppose find this aspect attractive.
Charles