This game is finished in a lot of ways. It has one of the best interfaces of the Paradox games. It's quite stable. I haven't seen a single CTD (!!) Generally, the opponent AI does quite well.
However, it's also not perfect. The rebel system needs reworked. Most wars end up becoming long, drawn out WW1-style affairs, which simply isn't realistic. The influence game for Great Powers is simply ridiculous right now. Imagine the trade system in EU3, only: 1. Great powers are the only ones playing, 2. Once you get a monopoly its almost permanent, and certainly long lived, 3. Second tier powers lose their raw materials as a result of said monopoly. Also, Italian unification requires playing the influence game, rather than unification via war, which feels really forced to me. Like all these states would instantly join Italy simply because I hit influence button once or twice. Or like Sardinia could've possibly become a great power without gaining Italy first.
Still, it's a good game with LOTS of potential. I think, once it's fleshed out, the influence game could be awesome. Imagine if having influence meant also having to protect said spheres: from opponents' influence during peace, from the spheres themselves during offensive wars, from the spheres themselves as they attempt to escape said influence (like Personal Union insults in EU3), etc. etc. I also like the idea that second tier powers would be given small influence points to try to: take themselves outside of GP orbits and even possibly influence nations in small regions around themselves.
Beyond this, the ideas behind the game are great. As the execution catches us, this could very well be the best game in the series. As it is, it's still a good game in the series, and better than HoI3, EU3, Victoria 1, Rome, and Crusader Kings were on first release. No question.