I would like to know if there's a PHP CMS which makes things like editing a block of text easy.
It also should let the user separtare content in columns.
I'm using Wordpress right now, but it seems like the only way of letting the user add content is in form of posts.
Take a look at MojoMotor it's different from the standard CMS packages and is based off CodeIgniter.
Joomla is the Answer. It has all the properties you mentioned
Wordpress allows adding pages too. These live outside the blog and are not automatically shown in the blog index.
If you decide to drop WordPress after all, you could take a look at 9 alternatives to WordPress.