Not sure this is what OP is getting at, but CSS is getting a bit bloated and yet is still unable to fulfill many simple tasks without extra divs and/or JavaScript.

With Flexbox we're soon going to have _sort-of_ solved one painful issue in css - lack of vertical centring, but it's amazing it's taken this long and that the solution is still so ugly.

Larger issues with CSS can't really be solved without breaking backwards compatibility (which will never happen). For example, I wish CSS was more modular and perhaps didn't cascade so freely as it does. It's very rare to see an old site where it's possible to modify the CSS without risking breaking random pages.