Stagger is basically the same as %DR. Would you be happy with abilities like Raw Intuition being changed to "For the next 6 seconds, you take 20% less damage. The damage that you would have taken is instead applied to you as a DoT over the next 10 seconds", with abilities like Equilibrium being replaced with Stagger purifying effects to prevent button bloat? There's a reason that these concepts typically exist on different jobs, powergaming fantasies aside.

It's actually relatively straightforward to balance out. What shifts the balance is if you turn it into a passive trait that you get for just breathing, but that's the same as giving a job higher baseline defensive stats than everyone else.