If you would like to do something about this, head over to the themes forum, and help out with what Amy Groshek is attempting: https://moodle.org/mod/forum/discuss.php?d=216519
Comparisons and advocacy
Yes, of course I can try to help there and I will - Amy, Mary, Danny, David, You and other people in theme forum have collected many good ideas to make Moodle Themes better. My comment was just a simple explanation why templating frameworks like Gantry and Warp can't be used directly with moodle.
Things like Bootstrap were not originally meant to be used on top of YUI - to make Bootstrap as fast and reliable as possible you should use it without YUI reset-base-moodle base-custom theme css overwriting chains. YUI css files have the contextual version, CSS Reset's rules should be applied to nodes that descend from a node with a class value of .yui3-cssreset only - not everywhere:
I can't even tell in which yui widgets yui reset is actually needed and why default styles of HTML elements need reset - we have dropped support for IE6 a long time ago and other (modern) browsers render css almost equally. It's a pain to overwrite hundreds of css rules just to notice that it breaks again in the 4th list element - ask Mary about different YUI reset css bugs and she might see red
Most common joomla template frameworks use either jQuery or Mootools - or both - for example Warp that Troy mentioned is using jQuery and Mootools for changing settings in administration and for creating different vivid effects and widgets on pages - see more details from pages like http://www.yootheme.com/themes/warp-framework or http://www.yootheme.com/demo/joomla/drive . And surely Yui widgets could be used as well if somebody just had the time and knowledge to create from a scrach a similar templating framework with YUI3.
The only "exception" in moodle 2, mymoodle theme, is using mobile jquery on top of yui and it was accepted to core only because YUI had no mobile options available.
Moodle 2 themes had many major improvements compared to moodle 1.X themes, for example output renderes, configurable settings, cache and free selection of layouts Special Thanks to You, Tim, and Petr & Sam. The unfinished parts can be added to moodle 3, right?