When I attempt to upgrade MediaWiki I currently have to write down all of the extensions, and ensure all of them are compatible with MediaWiki. With some subsets, I need to ensure they are compatible with each other (like SMW, SF, SRF). Now I'm going to need to do that and track the compatibility between extensions and dependency extensions. I'm actually going to have to write an upgrade matrix to upgrade, and that's not OK.
Why would you want to manually keep track of the dependencies when a tool such as composer can handle it for you?
To throw another viewpoint into the mix. If we require composer, we require users to learn to use composer. Some like myself have never used it, and while it’s a skill I should probably learn that will save me considerable time, it may be that not all will find being forced to learn a new piece of software so great.
Of course I could be missing something here.
Thank you, Derric Atzrott