The new Seal of Justice would be something as follows:
Causes your melee attacks (would also include judgment) to slow the enemy by x% stacking y times. When your target reaches y stacks, they are rooted by holy chains for z seconds, taking n% increased damage from the paladin.
The number of stacks should not be low enough that it has no chance to be countered, and also not high enough that it can be countered every time. The roots would be on its own DR to prevent not wanting to play with other classes that also have roots.
The increase in damage taken by the paladin should be significant enough that you would prefer it over truth even if the roots get dispelled/countered a few times.
Hand of Sanctuary would either replace Hand of Salvation or Hand of Freedom (Freedom being more likely). It would be a hand you place on a friendly target making them immune to CC for x seconds (most likely 3 - no greater than 6). This would mean Holy could pick it up, but they would be dropping Repentance to do it, so their CC train would be significantly weakened by taking this. A choice for sure.