We would be switching to the same software as minecraft forum, which currently runs curses own forum software, cobalt. I will personally be going over all the features in xenforo (what we use now) and making sure that if they are needed they are implemented in the new forum to the same standard we currently use. I hope to open up a test forum for everyone to go play with and give suggestions to where we should improve it before we move anything permanently. As for the slow downloads I'm not sure how you are having that problem, I have to say of the issues it has for me at least speed is not one of them.
As for gamepedia it runs on different software and servers so that's why it's quite different!
PS. If the WYSIWIG editor is really that bad it's not a big job to just swap it out for an off the shelf one so don't worry about that