Personally I'd just give us traited versions of the skills and add all base skills of the 2 base classes we are locked into. Gives all jobs a plethora of options. I mean if we are locked into 2 sub jobs and we get the traited versions on those jobs themselves would we not qualify for them? Come on now.

Either that or allow us to cross class from any base class.

Until that happens the "cross-class" system will remain a joke only taking skills you feel are mandatory which implies no choice at all.

Make the player feel rewarded for leveling all those classes up.