(Good) news from the PTR! Suicidal Zebra reports changes to Seal of Vengeance. I've not seen any crunched numbers but this looks a lot more promising.
In one of the PTR builds Seal of Vengeance would build dots to a stack of 5 and then start doing 33% weapon dmaage additionally as holy damage. It's changed now to start doing additional damage from dot 1, and goes up as more dots are applied.