It depends on what aspect of it you are talking about, and what time frame you are comparing it to. Drupal has a lot of nice features, and once you learn how it is structured, it's very easy to extend.
For that matter, the Drupal community have been trailblazers over the last decade in many aspects of CMS design and, in turn, what people and developers expect from a CMS. I'm not saying that it is perfect, and sometimes it lags in UI, but it is always moving forward.
Yes, it's gotten a lot better. This release replaces most of the underpinnings with Symfony, which is good modern PHP (and yes, those words can be uttered in the same sentence).