I strongly agree with the OP's sentiment - even though the game in question also looks like it's been well-played. 3 points to add:
1. The odd thing about the EU3-EU4 comparison is that I find the new game mechanics way cooler and starting out games it seems way more fun now. I couldn't even imagine going back to EU3. There's a strange disconnect between a game that makes me feel more and more like a kid in a candy store in 1444, and for the most part leaves me fairly cold by 1600 at the latest. One interesting indicator for this may be - if anyone's watching Quill18 or Arumba play on youtube - when do their games become boring to you?
2. I totally get the advice from people in this thread (and 100s of others when people ask "what should I play next") who say- play an OPM; play an HRE OPM; play Aztecs; no, play an Indian OPM, etc. And fair play, obviously those would be more challenging games, but generally I don't want to - and I don't want to have to. When I think EU4 I do think of the Age of Exploration, the 30yrs War, the [French] Revolution, the balance of power and all that stuff. So I want to play France, Spain, Austria, Brandenburg, Netherlands. Obviously that doesn't have to be everyone's opinion, but I'm pretty sure that few people come to EU4 thinking "I want to conquer the world as the Apaches".
3. For me the comparison with CK2 is very interesting. If you're not too abusive about exploits and min-maxing (I tend to be too lazy for most of it anyway), then gameplay at every level of the game can be fun for a long time (at least it did for me). If you play an HRE duke and by some fluke you find yourself crowned Emperor, often you're in for one hell of a ride. In EU4, if you're playing as Austria and you inherit Spain, it's game over. And that's a big shame.