The Paradox Forums now feature a new postmortem on Crusader Kings II, written by Henrik 'Doomdark' Fåhraeus, lead designer on the medieval strategy sequel (thanks Quboid). Like any good postmortem, this looks at negative aspects of the game's development along with the positives, so Henrik describes planned features that never made it into the game, and discusses how some of that will still be added:

So, what are we planning for the future? Crusader Kings II will have many major DLC packs that are actually more like small expansions. Every time we release a major DLC, we will also release a major free content patch. I cannot say exactly when we will be adding what, but here are some things you can expect for free in the coming months:
Enhanced, more focused Crusades with a "contribution" score

        • Causes of Death
        • Asking to join an ongoing war
        • Lots of more plots and ambitions
        • Events, events, and more events
        • Improved GUI where it's needed the most (plots, marriages)
        • Flexible de jure liege structure
        • More de jure kingdoms

Of course, we will also be fixing bugs, plugging exploits and improving the interface, the AI and game balance. Oh, and unleash some DLC...