What problem does this address?

Let's say I have a simple setup for my website where I need only a couple of templates: index (archive) and singular. When a theme declares a lot of templates, for example index, home, archive, page and post, I need to overwrite them all to get the same consistency. Then, when I want to change one thing I need to change them all again. This feels redundant and is hard to maintain.

What is your proposed solution?

In the template list, allow users to disable templates which are offered by themes. Then I can just fallback to only the basic templates like index and singular.