Of course it would be up to a theme or plugin developer whether to use the functionality or not, but a standardised system for including and managing css and js files would be useful.
It would reduce the page size, and load times, and might have a positive environmental impact with so much less stuff being sent.
It would be also useful when including scripts for things like adwords, managing fonts, etc.
Options could include where to insert scripts such as after <head>, after <body> or before </body>, and cachine, minification and combination functionality
speekless 