I understand what you’re saying but I think it’s such a non-problem. Let users make their own mistakes and allow the many of us that would really like to use stereo sounds for our music. If you take your example of someone trying to make a reference mix it’s as simple as either: Using mono samples or importing/recording in mono. And having a simple toggle option for each sample/track to use L/R or the sum of the channels.
Not being able to properly and easily utilise a unique stereo sound because mono has been effectively enforced on me is a much bigger problem than sometimes needing to do some channel management. I wonder if a lot of this disagreement comes from differences in music tastes and production styles, I think if you like to work very additively then starting from mono samples is great, but for myself I often like to start with a more dense wide soundscape and kind of alternately subtract and build up. More of an ambient style thing perhaps.