Markdown is good enough, yet for some reason, each platform finds it necessary to do something slightly differently. I really don't care about a WYSIWIG editor, as long as I can use straight text if I want. Basically, I want Reddit comments in instant messaging and bug trackers.
It seems every text input box across the product line has a different input method: BB, Jira, and Confluence. You'd think they might standardize with one to be less user hostile.
We are using Gitlab now. It's much more limited than JIRA, but for what it does much more coder friendly.
On the topic of the text box, gitlab saves the content if I start typing, get distracted, go somewhere else and come back later. That's handy. Unfortunately there is some inconsistency that it doesn't work everwhere, was it so that in Wiki pages it didn't work?
So, markdown?
Every website has its own flavor of it. Just reading some of the answers around here you can read "to do markdown better we made our own markdown".
Maybe because it is shitty. Just let users use HTML.
I think it'd require whole team that'd maintain that and a lot of tests on different browsers cuz browsers try to "fix" html and it may vary between them, meanwhile it may lead to some bugs(probably)
I'd suggest to try stay away from html as hard as you can and use those cool *down parsers instead :P