Drupal 8 has come a long way since Drupal 7 to being easier to use out of the box. When I built sites for people using Drupal 7 the biggest complaint was the lack of a WYSIWYG editor. At some point installing WYSIWYG module and adding an editor role just became part of my usual installation of modules. This process wasn't complicated, but it was rather annoying.
First you had to install the module, then download the third party WYSIWYG files from another website. Once you had all the components you needed, you then had to setup text formats to use the editing interface, and also configure the role for your content managers to assign correct permissions. My favorite part of the process was the web page of check boxes of buttons you could add to the toolbar. The page was hideous and not very configurable if you'd added any extra add-ons to your WYSIWYG.
Drupal 8 has eliminated all of this and refined the parts you need to do. Out of the box you have an editor — CKEditor. The configuration for text formats and editors are now located in one place. The default installation profile of Drupal 8 the editor configures your site for Basic HTML and Full HTML text formats. If you don't like the defaults, and want to customize the toolbar, the checkbox page of death has been replaced with a drag-n-drop interface. It's all so simple now!
Drupal 8 also offers some added functionality in the WYSIWYG editor without the need for additional modules. The ability to insert images in-line is now available out of the box. In my opinion this is still very rudimentary and should hopefully be replaced with media module at some point in Drupal's future.
Something new to Drupal altogether with the addition of WYSIWYG is in-line editing. In-line editing is the ability to edit content directly on the page the content is displayed. Not on another page, tab, or overlay; you can now click a link provided in the contextual links menu (now displayed on hover as a pencil) to edit the page directly. This actually works pretty well and has a slick interface. You just hover over the section you want to edit and are able to modify the content with a WYSWYG tool-bar hovering above the content. If you placed images in-line you can also swap them out and work with them directly on the page.
Drupal 8 is looking really good for site builders and content creators/editors with the addition of these tools. WYSIWYG is one of those things that either people really love it (end users), and there are those that wished it never existed (developers). Either way, we now have one in core, so take a look at this video to get a brief overview of the features it offers, what it looks like, and some caveats of where it can use improvements.