As an armchair point allocator, you can't go wrong with VIT no matter what. You're no good to anyone dead, and more HP helps prevent that.
Otherwise, it's a choice of accuracy, damage, more MP (if it's relevant), or more healing potency (if it's relevant). Personally, I'd look into what stat ends up being more expensive and /or rare, equipment-wise, and augment that. But if money is no object, you'll probably be pressured into a typical glass cannon build unless you're a healer or tank because damage is all anyone cares about.
DEX doesn't do accuracy anymore. It does physical ranged damage (ARC onry) and parry chance.
And actually, were I a tank, I'd probably be more interested in STR or DEX over VIT. Parry chance and block effectiveness seems like it'd be worth more HP than just having slightly more HP in the form of prevented damage.