One of my favorite things about MERP was that the adolescence (0 level) skill ranks where given by the culture of the character. (Table CGT-5, if my memory works fine)
This is something that have been implemented in some way or another in the different incarnations of RM, but if I'm not mistaken, only as an optional rule.
IIRC there was an issue of RMC Express Addition that had culture rules, they were handled a bit like training packages.
One of the things that gave so much flavor to Runequest character creation, was the whole profession/culture connection with the starting skills of the character.
I would love to see a well developed culture system in the core RMU rules and to have the adolescence skill ranks tied to the culture. This will give the perfect extra pinch of salt to character creation. (If any GM doesn't want the culture system, he can just do the adolescence level exactly like the first level anyway.)
As the core rules will not be tied to any gameworld in particular, the cultures should be generic, e.g.: prehistoric, nomad, barbarian, civilized, sylvan, hill...