Also, other communities that deal with a similar audience had the same problem with Markdown and moved back to BBCode. For example, these guys (http://guildwork.com/forum/threads/4e46f3d5205cb22721000765-...) moved from BBCode to Markdown and then ended up moving back and writing their own BBCode parser in Python.
Markdown is good when users have limited syntactical/formatting options. But BBCode makes it easier to extend features with an intuitive syntax that nobody seems to have trouble with.
One example would be Markdown's dependence on character glyphs:

[click here](http://google.com)
preformatted
text
While BBCode is easy to recall in plain English and you don't need to remember any glyphs or the order of them: [img]mypuppy.jpg[/img]
[url="http://google.com"]click here[/url]
[code]
preformatted
text
[/code]
Adding dice and a youtube embedder to BBCode intuitively extends the syntax set. It doesn't introduce any new symbols or anything. [dice]4d6[/dice]
[youtube]http://youtube.com/v?i2h38aoj[/youtube]
Finally, it's been half a decade since I used Wordpress and I think I'm way off topic here since, on second thought, I'm pretty sure Wordpress just offers a WYSIWYG editor that lets you drop into html. Doesn't even use any sort of BBCode-like syntax. :O)