Greetings, WAI-IG and all:
I will do my best to assure cross coverage, i.e. post the link to this
discussion to the WebAIM list.
As it happens, there's a very similar thread just started on the WebAIM
list that some here may find helpful:
Accessible CMS for writer AND reader? Contao? Wordpress? Ghost? Other?
And opinions of Markdown for authoring?
<http://webaim.org/discussion/mail_thread?thread=7179>http://webaim.org/discussion/mail_thread?thread=7179
I would also suggest that being aware of ATAG 2.0 would be very much
worth considering, as well as mentioning it to the supporters of the
CMSs you're considering. Start here:
http://www.w3.org/TR/ATAG20/
But as with most W3C guidelines with which I've worked, it may also be
important to consider supporting documents related to the
recommendation, itself.
Best,
Jennifer