I think, piercing is a bit of a red herring considering trick attack, I mean you could try and give trick attack to another job, but then why not bringing that job + NIN for double trick? I mean piercing is strong and all but triple melee kinda works too, they could try to create a caster comp in some way to kinda balance it, but even then NIN would still be ther and once piercing gets resolved in any way it's only a matter of time that they'll become the focus of ppl hate just as piercing is now