Both joomla and drupal come with their own set of challenges from a maintenance point of view. Wordpress...well, it's actually gotten to be pretty easy.
Bottom line, what exactly are you trying to accomplish? Are you looking for a blogging platform, a hybrid platform, or a CMS? What do you want it to do?
Wordpress is not the only blogging platform out there, and joomla/drupal aren't the only CMSes out there.
On another note, if you want to keep your CMS separate from your blogging platform, that's no problem either. Some folks do that. You don't have to use "one platform to rule them all".