I never use any succession law but elective, since you can always choose the 20 year old nephew who is a strong genius grey eminence, and not get stuck with the misguided warrior drooling imbecile that is your son.
I have played the game around 120 hours, and I've never lost an election (~100 of which was with elective), and I've never even *tried* to win an election; you pretty much automatically win.
what is the point of having primogeniture / seniority / open succession (even open/turkish succession is far worse than elective)? I understand gavelkind has a demesne bonus, but considering you lose half your demesne when you die, that also looks quite bad.
I'm playing primogeniture since I'm now leaning towards elective law being an exploit.
Well, there are some problems with elective when collecting kingdom titles befor becoming an empire. You might not be able to elect you canditate in all kingdoms or some kingdoms will have different succession laws and you can not change them.
Combination of gevekin/primo/elective could easy fall apart and destroying kingdom titles are a bit expencive in many forms.
Now, if you create a new empire and have elective, it will start in gavekin, which will create problems, as changing succession law in big empire is near to impossible. I did lose election some time in small kingdom, if you do not have adalt male relative to ellect and there popular duke.