Although it may be complete overkill and in some ways it is rather bloated.I don't understand what you need that Joomla doesn't provide.
You can do all the things you ask for by logging into the site as an author and going to the correct category and clicking "add article"
The only downsides I can see are that the free templates can be a little bit rubbish (see my site www.digimatic.co.uk for an example of a bad template that I haven't got around to tidying up yet) but you can just start with something close and modify to suit.
and that site structure changes would require logging into the admin interface which there is a lot of in joomla so adding new categories can be pretty daunting for non technical users.
My own joomla installation really only exists for the purpose of playing with it and the various plugins. If you want a author or admin login to mine to play without having to install it first then mail me off list