It seems that I hear a lot of people within the Drupal community focusing on how to make Drupal scalable. This is all well and good, but Drupal does scale; the Emmys know this, the Grammys know this and so does the Economist. Drupal can handle millions of page views in single day and frankly this isn't an issue that most websites face. This single biggest argument people have against building a website in Drupal is that it too complicated.
So does Drupal need to be complicated? Absolutely not! As Drupal service providers our job is to build something that's not only high quality but also to make the user experience during and (maybe more importantly) after development easy. Drupal 7 is a great step in this direction, so let's get it out the door. Let's focus more attention on administrator workflow and making some of the more commonly used features of Drupal (like blogging) more easy to use and more intuitive. Let's attract more designers and non-developers to this fantastic platform.
The usability of Drupal affects every Drupal user. So let's leave the scalability question to Dries and Acquia and start focusing more on making Drupal sites that are intuitive, easy and a joy to use.
I'd like to start out by apologizing for not recognizing the contributions of more people in my initial post; I don't want to under value the work that has been done on Drupal to-date. Notable companies/people doing scalability work include Chapter 3, Four Kitchens, and countless others.
As for UX, as merlinofchaos mentioned you can get a sense of who's active in this movement in terms of improving the codebase at:
As I already mentioned, I think that Drupal7 makes great strides in improving the usability of Drupal.
With that said, the reason that I posted this article is that I think that during site building by service providers (this is important) strides forward in UX tends to take a back seat to how many visitors the site can support. I hear a lot of buzz about high profile sites switching to Drupal and not as much about how Drupal is making people's lives easier.
I know that people who are excited by scalability are going to continue to work on this and continue to push the envelope getting bigger sites on to smaller hardware. That's great! I'd just like creating fantastic user experiences within Drupal to be seen as just as important and get the recognition and attention it deserves. Great users experiences will attract more people and increase Drupal adoption rates - and that is good for everyone.