Vengeance has been the core defining talent for the Retribution tree since the beginning. It has been nerfed in the latest Beta patch. It was reduced from 15% damage to 10% damage.
In the same patch, Warriors got the following talent:
Requires 45 points in Arms.
Your melee critical hits have a 100% chance to enrage you, increasing all damage caused by 15% for 12 seconds.
There are some *really* upset paladins on the WoW forums.
Edit: Latest joke on the forums, courtesy of Skye of Hellscream:
Q: You know why Vengeance got nerfed right?
A: Duh. Vengeance got Nerfed because the talent was too similar to Wrecking Crew and had to be changed to preserve class uniqueness. Obviously.