WordPress offers the core set of features for a CMS vs just a website tool, but sometimes your needs will not always be best met with WordPress.
First let's talk about what WordPress offers in terms on content organization. WordPress offers the three primary features of a CMS.
- Content-types, or known in WordPress terminology Custom Post Types, which allow you to create different types of content each with their own set of attributes and behaviors. You can create your own custom post-types in WordPress with code in your theme or through a plugin.
- Taxonomies allow you to create loose grouping system. WordPress has categories and tags out of the box but just as with custom post-types, you can create your own.
- Fields allow you to create custom attributes that describe the details of the content-type. WordPress has this but many people use plugins to help with this. A popular one being Advance Custom Fields.
Why might you want something else?
In terms of CMSes, WordPress has closed much of the gap between many others. Where you still might not find WordPress suitable is that you really need a "webapp" more than a content oriented website. In that case, you may either need to find a tool designed for that domain such as an online store or build the site using webapp framework such as Ruby on Rails.