markdown edit mode
I would've added both Bugs and Design categories if they were tags, but my suggestion is to bypass current issues so hopefully it fits. Markdown rendering in the Wiki tab is currently done live as soon as it's added. This causes several bugs when editing a wiki page, doesn't support editing markdown without completely replacing it and prevents being able to easily copy/paste content from another wiki, .md file, etc.
My suggestion would be to only render markdown when a user is not in edit mode (wiki page>section is not focused). This would allow all of the above functionality and most likely fix a majority of the small rendering bugs that currently exist. It would also be an easier route to take for the dev team because it would remove any expectation of things working live.
If the original idea was to have live functionality so that multiple users could edit at the same time, I would think that the addition of "so-and-so is editing this section" is a good enough compromise. I haven't been editing the same team>channel>page>section as someone else on my team before, so my guess is that's a rare occurrence for most.