Two points I'll comment on:

People truly underestimate the Stun on Shield Bash. Sure, it's not 100%, but against things the Darkhold Ogre or Coincounter, you'd be VERY surprised at how often you can stun. And there is nothing more satisfying than stunning Eye of the Beholder or 100 Tonz Swing.

The second point is the way people are underestimating the Defense Down on Riot Blade. The example I present is Miser's Mistress.

When you're DD are going all out, the Defense Down increases their damage potential, as well as gives you a little bit of a hack and slash as well.

To best utilize Riot Blade against Miser's Mistress, use Outmaneuver and Divine Veil against the Banemites in the area just before Mistress's room. Have the rest of your party enter and start activating the glyph. By the time the banemites "Retreat to the void", you'll have build up a reserve of TP to be used against Miser's Mistress. This will let you Phalanx, Spirit's Within, then Riot Blade/Rage of Halone.

Chances are, you're using MNKs, and in more cases than not, one of the shoulder tackles will stun Mistress. This gives you the ideal conditions to run behind her for Riot Blade. This also puts you in a prime location for your Rampart to hit just about everyone. Then you simply run back in front of her and use Rage of Halone, at which point your regular tanking cycle can continue.