There are some rerally important features that make a great CMS. Since the main issue is usability with the current cms, this is going top be the main focus of the redesign. Simple adjustments that will make a world of difference to the user.
The content needs to be easily editable and this is one of the key features of every cms. Therefore a great question is whether to use a top-aligned editor or an inline editor? This is reasonably easy to answer, the main editor should be available at all times while the inline editor should be available in a live edit mode. A great inline editor is the medium editor (https://yabwe.github.io/medium-editor/).
The user must be able to see images via upload date, and also search for file names, they should be able to delete or upload images to the assets section of the site.
The help and search feature is an important one, it offers users with no technical know-how information regarding a specific topic they are stuck with. For example they could search questions into the guide to get specific help with something, they could search for the title of a page they are looking for so they can edit it quickly. This feature could save the user from wasting valuable time.
Customisation of the site should vary depending on the users needs. The majority of the sites the client designs for are predesigned and should not allow for further editing. That said, should the company want to update the looks of their site they should be able to without having to pay the company more to do so.
Customisation on a smaller scale could be like allowing the user to update the colours used in the navigation bar or site wide fonts.
Versioning is a great feature that allows the user to have the safety of knowing that if they accidentily content, they can revert to an older version of the site. This makes it easier for them to update the site for short periods of time with short promotions etc with the ability to easily revert.
Social Media Integration
Social media is such a large part of running as business today, it should be relevant for the organisation to have a hub of all the social media on the site. The site could pull the integration even more into the design so that when the site developer adds a story to the blog they have the option to easily share the story through their social networks.
Analytics should offer the organisation an outlook at hit views so they can track success of their posts on the site, what sections are most important to their users. Allowing them to move forward with enhanced knowledge of their business.