Is there any way to intervene in vassal revolts directly? I was recently able to install my son as king of Gerogia but one of his dukes revolted and it doesn't look good for him.
Fair points. I certainly don't advocate that you undermine major game systems for a minor issue. On the other hand, is my 3rd option infeasible (or in your educated opinion, a poor mechanic)?
I mean, its kinda the mirror of the coronation system. A new ruler is not given the deference of an established ruler. At the same time, the handpicked lieutenants of an established leader are generally given deference (until they overstep themselves). We, generally, shouldn't see the common situation of appointment immediately followed by revolt simply because the subordinate vassal has a bit more power.
Well it says your allowed to intervene if your vassal is fighting a holy war, which I guess is useful if you have vassal kings next to infidels. Is it not as simple as changing the required flags for intervention?
I'm not really sure what you're going for with that suggestion, to be honest. If it's supposed to be that you appoint a character who goes around "enforcing the peace" on your behalf, then it's still mirroring the Enforce King's Peace system...and that's not something I'd want to do (not without ripping out the current King's Peace system entirely and replacing it, which is no small undertaking).