On the nesting point, you’re on the money. When people using nesting as a way of documenting the exact hierarchy of elements in the DOM, and you get selector specificities of 300+, I die a little inside. Nesting is not documentation. That said, there’s always an unavoidable case or two of needing to prefix n selectors with the same parent class and nesting can come in useful there if used in moderation.
Also why on earth would you create a file-listing (by which I assume you mean, “sequence of @imports”) alphabetically when you know — as a CSS developer — that specificity is vertical? I have no doubt some noob might do that, but there’s no point in citing inexperienced mistakes as reasons not to do something.