Yeah, CMS is now an e-Learning solution meanwhile you need the one to make your site look like heaven for your students.
What concerns Joomla I believe they really had to rebuild the entire system from the ground to implement this heaps of new features... http://magazine.joomla.org/issues/Issue-Jan-2012/item/654-What-s-new-in-Joomla-2-5
As for me feeling of Joomla changed a lot after they added nested categories - you don't have to create sections and then categories and use categories only. Besides Joomla 2.5 runs on both MySQL and Microsoft SQL Server what makes an awesome difference.
As for e-Learning solutions there are two I'm using for my clients (it depends on their needs which one I suggest):
JoomlaLMS - Joomla native component, perpetual license never expires and code is open
Moodle integrated with Joomla by Joomdle - wonderful solution for clients who stuck to Moodle
Opinions on Drupal and Joomla are conflicting. I think Drupal is supported by freelancers mostly whenas Joomla community supporting this CMS consists of a huge number of professional companies. To my mind Joomla rocks.