Last month Drupal 7 made it's first stable release and we have leapt at the opportunity to make use of it in the redesigning and rebranding our website. There are loads of exciting things in Drupal 7, bringing flexibility, convenience and even better performance through improved caching techniques.
However, Drupal 7 heralds the end of the throttle module. It has been around since Drupal 4.6.x and as of November 22, 2008 was extinguished from Drupal 7. According to that last link, Dries hinted that it would go back in 2008. It is not considered worthwhile given that there are other mechanisms available in D7 (e.g. aggressive anonymous page caching) that offer far better ways to prevent low-traffic websites being slash-dotted.
I don't really have any big arguments against this, but earlier today we were having a think about a site we're working on that needs to be incredibly dynamic for anonymous users, and yet will need to handle high traffic. Having a framework in core that allows our own modules to intelligently drop features in times of peculiarly intense traffic may have turned out to be useful.
Of course, the best solution lies in smarter caching. And if there's anyone who desperately longs for throttle-ability, it can become one of the many reasons to build your site on Drupal 6, rather than stepping into the shiny new world of Drupal 7.