Yes, I’ve actually used this idea to build a site, we called them panels. The client can create a panel with 1, 2, 3 or 4 columns and specify much of the formatting used. The main content area is removed on these pages.
The main problem is that the standard WP search will not search this content. You need to install something like https://wordpress.org/plugins/search-everything/
One other thing that you may run into is the admin timing out if too many content areas are added. On another site I built I the client has up to 7 content areas for each section plus quite a few fields that control the layout of these fields on the front end. At about 10 sections using all of the available content areas for them (70 wysiwyg fields) the admin might time out when they save the page.
