I can't say I don't like this idea. Theme weeks are usually a pain only because I have to rush something out that isn't up to my own standards but whether you like it or not it does add some variety to the season. Do I wish there was something else that added some variety to the season, you bet, but it seems so far that no one is interested. Plus, if content is king, it isn't bad having a reason to create more.
Wait till after S100 to get rid of it though as a S100 theme week is a must.