A big part of content maintenance (for users as well as the company) is reviewing and updating published content. In order to be transparent, it is oftentimes better to not remove outdated sections of text, but to strike through it. This way users can still see what the old information was and can compare it the updated content.
Currently there is no way to create strikethrough text in the frontend. It is only possible in Control when you manually use the <s> tag in the HTML mode.
I propose to add a “Strikethrough” button in the text editor as several users in my community and also staff members are requesting this feature.
As there is limited space in the Text Editor toolbar, I suggest to do a global usage review of the existing formatting options and to remove the least used one (my guess would be the left/center/right align format) in order to replace it with “Strikethrough”.