As a vassal, I try to ask my liege to become a March instead of a vassal, but one of the -1000 modifier is "too high development compare to liege", which I don't really get...shouldn't it be the stronger I am, the easier my liege is going to accept my request? Do I need to become weaker or wait for my liege to become stronger in order to promote? It doesn't really make sense to me...