Many sites would like to add a proper forum to their site and are running WordPress as the front-end of their site. They already have a userbase and WordPress manages their members.
The addons currently here on Xenforo dealing with WordPress all make Xenforo the master and WordPress the slave. A WordPress site that is already running is NOT going to move all it's users over to Xenforo when it has WordPress plugins that depend on the WordPress user tables and member database.
What is needed is a nice addon that allows existing sites to simply add a forum to their site.
* When a WordPress user account is created, create one in Xenforo.
* When someone logs in via WordPress, have them be logged into Xenforo.
* When a user changes something in WordPress (such as their username, email, etc.), make the change in Xenforo. And vice-versa in Xenforo to WordPress.
* Add xenforo commenting ability to WordPress posts.
* When somebody logs in via the Xenforo forum area, have them be logged into the WordPress side too.
* When somebody logs out of the Xenforo forum area, have them be logged out of the Wordpress side as well.
* Sync both WordPress and Xenforo so everything matches.
Right now, sites are cobbling together inferior solutions such as BBpress, Simple Press,l Vbulletin or Vanilla Forums just to add a community section to their WordPress site. Xenforo would be an ideal solution.
With WordPress now powering 18.9% of the Internet, the market is HUGE and there is strong demand. Whoever comes up with a viable solution, will be well rewarded by the market. It's too big and simply can't be ignored any longer.
WordPress will only get bigger from here.