GTAKid667

Back in the day (long ago), nearly every project and development I know about used CKEditor. In its heyday (gold age), WYSIWYG editors were still a relatively new concept (I feel old. ), and CKEditor was considered top of the line. Times have changed.
Ideally, you want your editor not to be the focus of your development. By that, I mean to say the editor should blend effortlessly in the background as something you do not notice (an afterthought). So many developments no longer use CKEditor because the editor itself often gets in the way.  I cannot count the many times when I have heard or experienced why something was not functioning right because of the editor.  Or why something could not be developed or extended because of the editor. The editor (CKEditor) is not the afterthought it should be.  Even here on Invision, the editor and its limited functionality has proven problematic by the sheer request to work around it https://invisioncommunity.com/search/?q=editor&quick=1&type=forums_topic&nodes=499
Speaking personally, I love where Invision is going. I admire their creativity in where they are taking the development. I enjoy many of the features and am looking forward to the new features they have suggested they have planned. But I dislike the editor. It is my 'pet peeve' for Invision. I know of only two developments that still use CKEditor (the other is not a forum, and they use CKEditor 5). In both of them, I dislike the editor (v4 and 5). Why? Because in both of them, nearly all the issues I encounter, all the bugs I stumble upon, and all lack of functionality and adaptability surround CKEditor.  Besides Invision, only vBulletin, whose market share is shrinking and development has become stagnant, concerning forum software, still uses CKEditor.   
I do not expect Invision to change editors overnight. As SeNioR- pointed out, it is not easy to change editors, not even to CKEditor 5.  So regardless of the discission (whether we stay with CKEditor or change editors), we are still looking at a large transition. We have two (2) years to think this through and explore our options before CKEditor 4 reaches the end of life. Plenty of time to think this over.
You'll note I did not specify any particular editor (besides a few examples I gave). My request is not to promote any specific one, only that an exploratory investigation be conducted and that Invision considers their options.
 

CKEditor 4 is reaching the end of life (source). Instead of jumping onto the CKEditor 5 bandwagon, I propose Invision consider an alternative editor. There are many well-established modern editors such as, for example, TinyMCE, Froala, Quill, and Redactor, to name a few. Any of these would make satisfactory alternatives.
 
CKEditor may be 'old school,' but it has become bloated, larger in file size and load time.  Most of the issues it encounters often have to do with responsive layouts on a mobile device and excessive load time. As mobile continues to dominate the landscape, I feel it may be prudent to focus on an editor development that has kept up successfully with the times with the least issues.
 
Changing the editor should not be expected in the next release. But a roadmap should be considered for a future transition.  Thank you for your time and consideration. 😀