For authoring, nesting media queries, support queries, etc. is certainly nice, but you’d definitely wanna run it through a tool that can group or it’d lead to a lot of bloat.
Nesting can be taken too far when done deeply as it can lead to overly-specific or tied to a special DOM layout that can be less than idea. Pseudo selectors and pseudo elements seem like an obvious win, as can something like a lightweight markup syntax parser echoed into a <div id="Content"> where you can override easily all the inner elements that would be a hassle to slap CSS classes all over requiring an HTML parser in the build pipeline. Additionally nesting will certainly open up new minification options.
Design wise, oof, ’90s distressed typography had its place, but I don’t think the surprise text displacement on hovering hyperlinks wasn’t one of those places–especially in the body copy.