I agree, the cross class skills in this game are woefully underutilized. Take Mara/War for example (as it's a similar story with nearly every other class/job), as a Marauder I have access to 28 different abilities from the other classes; however as a Warrior I only have access to 10, and one of them (Savage Blade) is 100% worthless. It's pretty much the same with everyone else as well. This problem, combined with a terribad Materia system and BORING itemization is a HUGE blow to this game.