AC and WB are similar to how the WoW forum and MMO forums were - high volume of posts, low volume of new threads, with compatible demographics.
By merging the two:
* Writers get more exposure, and more critiques
* There's one less forum on the main page
* More people can poke fun at Jim's forum name
I don't even think there will be much resistance as was the case with the WoW/MMO merger because neither of these forums have a massive community built around one genre. We'll just be desegregating art, not pushing two very different communities in to one.