Saying Joomla development is a trivial task would be a lie. You'll agree to that as soon as you recognize Joomla as a huge PHP Application Framework. And it of course always takes some time to get used to a framework like that. Incidentally that's the situation for all frameworks of this kind, whether it's Drupal, the Zend Framework or whatever software you like. So it's not just a Joomla property and no reason to choose another framework at all.
Today I let you participate in my odyssey through two of the CMS stars at the PHP sky. Drupal 6 and Joomla 1.5 are the latest generation of CMS. Both are also announcing themselves as PHP Application Frameworks and both have a powerful developers community behind them. At a brief look these CMS seem to have good concepts behind them. In this article I talk about Drupal. My Joomla experience has just started and will be the topic of a later article.