Nah, just have an "Oh shit" macro that equips the same damage taken- gear you have for every other job. Then assuming you have maxed killer effect merits, best case scenario gear, and Ferine body+2 you'll have 80% DT-% 4mins/5 while killer instinct is up, and 57% for the one minute it's down and take hits better than everyone but PLD.

If you're using jugs, which you should since it will always let you have the correct pet family for killer instinct, you can just snarl onto them for the 1 minute killer instinct isn't up, if you're somehow getting too reamed to handle healing. I'm sitting at 29%/51% right now and I can almost always heal myself just with /DNC so long as there's just one enemy, since I usually am only taking double digit damage per swing.