I'll probably start off with a fairly simple European nation to gently familiarise myself with some of the new mechanics. Maybe Hungary, Lithuania, Burgundy. Someone like that. After that I'll probably move over to East Asia to play with the Emperor of China mechanics. Who I pick for that run will probably depend on what interesting achievements they add. Beyond that, I do want to do a double emperor run at some point. Great Horde -> Golden Horde -> Emperor of China -> Holy Roman Emperor sounds fun. Possibly even switch to the Roman Empire at the end for maximum "I am the true heir of every great conqueror and empire ever". I also expect that this will be the patch when I finally get around to trying The Three Mountains. Provided that tributaries don't count as independent, which I don't think they do, it seems like it should be a pretty easy achievement to grab in MoH. Finally, completely unrelated to the expansion, I think I'm going to have another go at a Sikh One Faith. I tried doing that a couple of months ago, but didn't manage it, but I know a couple of fairly major mistakes that I made, and I think I'd have a better shot at it if I tried again.