Aaah, the voivodeships themselves, now I get it. Yeah, they were indeed elected among the boyars, or even from the intervention of the Porte (like how the Phanariots were elected). Indeed, a great amount of backstabbing and power-struggles happened because of said elections.Voivodeships weren't standard hereditary monarchies like in the West, they were a sort of elective monarchy that were chosen by the local magnates but sometimes by the influence of regional powers or their suzerain. Ottoman suzerainty over the three Balkan principalities circled around the Porte and their candidates for voivode. It's something that the game completely ignores and I've never seen a mod that tackles it.
But history is one thing, game-mechanics are another. I do agree though, elective monarchies of any kind could use some more improvements/additions.