They may just be delaying the cross-class sharing until Heavensward. The big problem right now is that any job that gets access to Perfect Dodge, Goad and Death Blossum in addition to its existing cross-class skills will have an advantage over those classes who do not have a 3rd class to cross-class with. Each class will likely get their 3rd cross-class skill set when Dark Knight and the as yet unnamed Gun class are introduced in 3.0.