If you wanna talk real-life problems, that's an insignificant problem.
The biggest problem is that you're the one in charge, and you're immortal. Even if your faction leader dies, you'll still be in charge of the actions of the new one, and since you're essentially a godlike genius thanks to your knowledge of how the game works, that means every single faction leader you ever have will also be at that level of genius. Even having your avatar stabbed to death on the senate floor wouldn't stop you!
Where as in real life, when the old ruler dies you basically roll the dice on your new one and hope you get an Augustus or a Trajan rather than a Nero or a Caligula, while we in-game get a non-stop chain of Agustus-level leaders who all share a singular vision cross-generations. If rome had been that lucky in real-life the empire would probably still have been standing to this day.
Anyway, pretty hard to replicate in a game. Even the ones that try, like Crusader Kings, still leave you with the problem that, even though your faction leader has different stats, you're still the one guiding every successor's actions, so after you've dealt with any instability resulting from a change in ruler (which is easy tanks to game-knowledge), you're right back on track.