After struggling for some time solving http://moodle.org/mod/forum/discuss.php?d=123250 I think Moodle's CSS file structure really could and should be simplified.
Another disadvantage:
As Moodle compiles all those CSS files before sending the CSS to your browser when working with Firebug the line numbers it gives you are useless for actually finding the relevant CSS in your Moodle file(s).
If you want to use separate CSS files you should separate them by semantic criteria (e.g. core, modules, activities...) not by presentational aspects (color, font, layout...). Chances are that you want to change all presentational aspects for a certain module (the chat module for example). You should only have to sift through one file in that case, not at least three as it is now.
Is there already an issue in the tracker so one can vote for it?
Cheers,
Frank
PS:
Great quote! We should give them a place in Moodle Docs to live in