Well, yesterday's DD and especially the discussion in that thread made me change my mind from considering whether I should buy a new computer to make EU3 run smoothly to wondering whether I'll want to play it at all or just stick with EU2.
Don't get me wrong: it looks like there are going to be several lovely features, but I'm really afraid that Paradox's new product will lack the things that made EU2 the best game I ever played.
I even think that basically the new monarch system is a good idea, simply because it will allow for representing dynastic politics, which were of immense importance during EU's timeframe and without which playing Austria or Brandenburg-Prussia doesn't really make much sense (becoming a strong country just because of freeby events instead of as a result of a clever dynastic strategy is not what a game should be about).
However, I see two problems:
1. As pointed out, there is the risk that the game will become too generic. It will definitely lose a lot from its learning effect while playing and the possibility to interact with cool historical personalities like Frederick the Great, G2A or Elizabeth (in one game, I know that it will be possible to start at any historical date). Although these are things that contributed a lot to EU2's flair, that could be ok if it is the price for a more realistic and flexible gameplay.
What would entirely break the game however is if it became too much like CK, in the way that all countries don't play much differently. The greatest thing about EU2 is probably its almost infinite replayability.
Therefore, I sincerely hope that Paradox will keep in some specific characteristics for each country beyond its scenario setup. Just as an idea, I think it would be very cool to be able to define certain attributes for a nation's ruling dynasty, that will make its generic monarchs special and give them an individual "feel".
2. I don't want the game to be too "unpredictable", as Arilou put it, in a certain way. On the one hand, it is entirely desirable to avoid straightjacketing a player and to make the game adapt to a player's decisions and actions instead of triggering historical events in situations where they are just absurd, like a bankruptcy for an entirely prosperous Spain or a two-province France creating the Chambers of Reunion. Any improvement in that direction would be great, and appreciated by an overwhelming majority of the players.
On the other hand, what I'd hate to see is the game becoming entirely random. Ideally, ahistoric developments should only come as a result of player actions. Of course, there is a massive butterfly effect, but I'd like other the development and actions of AI countries to usually be historical as far as they are not affected by player actions.