Ok... I'm 70 years . And I think this is a problem. While "Elder" advisors are good to have around, the LEADER needs to be physically vigorous, mentally SHARP, and possess the charismatic qualities of the "Warrior/Scholar".
If you can't stand up to the opposing, and allies' leaders, you're unfit to rule. And ruling, regardless, of the mechanism, is what the leader is supposed to do.