Contrary to the Final Fantasy series, when Koei gives you Romance of the Three Kingdoms XI, they're really giving you the 11th iteration of the exact same game. That's a lot of refinement, folks -- and it's a testament to the series' lasting ability to capture the hearts and minds of strategy fiends.
The problem is that the series has seen so many little additions, tweaks, minigames, extra layers, and characters over the years that it suffers from what you might call "feature bloat." It does a hell of a lot of things well, but it does a hell of a lot of things. Even diehards will likely feel overwhelmed. R3KXI tries to help you with some surprisingly polished tutorials (this is one game that had a fantastic localization), but the game's console roots ultimately hamstring the playability. It's missing a lot of the tools that PC strategy veterans have come to expect, such as hotkeys, rollover tips, and context menus -- which contributes to the general sense of "what the hell is going on here?" throughout the game.