Europa Universalis IV's [official site] fifth expansion will be released on February 26th. It adds automated land and sea exploration, with chained story events involving expeditions to the New World, as well as increased depth for Aztec, Mesoamerican and Incan cultures. Separate to those thematic expansions, there will also be a custom nation building tool, with RPG-style point allocation for national traits, leader stats and territorial possessions. There is also an option to begin with a randomised world, reminiscent of the Shattered World mod for CK II.
I spent an hour playing around with the expansion last week, most of which was spent poking at the nation builder and chortling at the ludicrous scenarios that the randomised world creates. Occasionally there'll be a huge blob of a country staining Europe, or a mostly united Africa. It seems like an excellent addition for anyone who has played EU IV enough to learn the likely eventualities stemming from the historical starting point.
It's hard to analyse the automated exploration and added depth in the nations of the Americas after a short burst of play. I tend to stick with the European nations but perhaps the expansion will change that. El Dorado doesn't seem as extensive as The Art of War, which is fine - there's room for smaller additions as well as overhauled mechanics - but unless you're looking for new challenges, this might not be an essential slice of strategy.