What do you mean players don't play realisticly? Are you saying that the AI should take better stock in strategic importance, but players should follow history? Thats some hogwash.
Players are the best AI ever. If you want a game to challenge you, players will. So what if a player doesn't colonize south america as Spain and instead builds a crapload of cogs and lands 80,000 troops on English soil? If you want historic realism why bother playing this game? I can just sum it up for you: England Spain and France all got really powerful and then got really weak, the rest just stagnated, and/or vanished. End of game.
Will someone please explain to me this paradox of everyone wanting historic realism and open endedness at the same time?