Hand of Reckoning is a decent spell mechanically. The fact that it can crit is pretty funny, especially with Retribution, as it starts up Vengeance.
But the name really disappoints me. Back in April, I noted that Blizzard does a really good job with class names, and that I felt it added a lot to the flavor of the game. But in Wrath, it feels like Blizzard is phoning it in when it comes to paladin ability names. It bugs me because this was something Blizzard was so good at. It feels like Blizzard decided that names were too small of a detail to spend effort on.
Let's take a look at some new paladin ability names:
Divine Storm - Okay, this one is pretty awesome. "Divine" is being overused a bit (Divine Protection, Divine Shield, Divine Illumination, Divine Favor, Divine Intervention) but it just works here.
Divine Plea - Umm, yeah. This is just overuse.
Seal of Corruption - Corruption is a warlock word, and is really unsuitable for a paladin ability. I think Blizzard is trying to fit it in with the Blood Elves, but I thought the Blood Elves got redeemed. I think Blizzard could extend Vengeance to the Blood Elves without issue.
Seal of the Martyr - this is pretty good, though unnecessary. Seal of Blood can fit Alliance paladins too.
Hammer of the Righteous - like "Divine", "Righteous" is getting overused. But this one is okay.
Shield of Righteousness - This is just laziness, coming after Hammer of the Righteous.
Hand of Reckoning - This just does not make any sense. Hands are the old Blessings, short-term utility buffs cast on allies. This spell is not a Hand in any way, shape or form. And "Reckoning"? What does that have to do with taunts? This name feels like Blizzard picked a paladin word out of a hat, slapped the "Hand" prefix on it, and called it a day. I don't see how anyone who actually plays a paladin could sign off on this name.
I'm going to reiterate the suggestion that this ability be renamed to Rebuke. It's short, snappy, and has nice religious connotations which are perfect for the paladin class.
It also matches the taunts of the other tanking classes. Warriors Taunt opponents, bears Growl at them, death knights issue Dark Commands, and paladins would Rebuke them. All words with verbal connotations, but each infused with the separate unique flavor of their respective classes.