Does Draji Palatial Practice (4e) apply regardless of whether the attack hits or misses? The phrasing is "when you use", not "when you hit".
From Dark Sun Campaign Setting, page 107:
Draji Palatial Practice [Arena Fighting]
Benefit: ... When you use a power associated with this feat, the target takes a —2 penalty to attack rolls until the end of your next turn.
It seems to me that you can give a round-long automatic -2 to-hit penalty to whichever enemy you choose within range, and the power doesn't have to hit. The flavor is good -- you're so scary you frighten them even without hitting them -- but it's a strong feat, and I couldn't find any errata.