Of course on the otherhand, cross-classed abilities are still very useful and can make all the difference in a fight - you just have to be wise which ones you use and which ones you ignore, a task made harder by the smaller pool of abilities to use from when a Job crystal is equipped.
Nah, it's made a lot easier. A lot of jobs don't even have more than four or five cross-class abilities which would actually be worth taking, so there's usually a clearcut selection. Off the top of my head the only one which has serious argument over which ones to take is Warrior (Provoke may be non-negotiable, but then there's arguments to be made for every other skill except Savage Blade and maybe - maybe - Haymaker, depending on what challenges you're getting into and your personal objectives/style).


That said, to be clear to any new players who are reading: 99.9% of the time, your Job's unique skills that you gain (as well as equipment access and bonus stats) are more valuable to you than anything you lose out on as an option in the process of becoming a Job.