Rewards Patience.
As your nation gradually becomes more powerful and you just want to keep playing and see what happens next. Changes take time but there is a strange satisfaction you get when things start to roll.
The economy and political model is amazing, who knew these two subjects could be so interesting. Warfare is much more streamlined and easier to wage than in f.x. Europa Universalis 3, although the a.i. could be polished.
Diplomacy is also a bit fiddly and involves a lot of micromanagement and a option to annex a nation peacefully would have been nice.
All in all a great game and I look forward to see it expand in the future