Dauntless Champions
One sentence, and it is narrower than it first reads. When a friendly PALADIN SQUAD unit is selected to fight, if the Strength of those attacks is lower than the Toughness of the target, those attacks have +1 to wound rolls. This is a punch-up rule and nothing else. Against a target of equal or lower Toughness it does absolutely nothing, so the detachment is worth a Detachment Point only in a meta where you expect to swing into things tougher than you are. What it fixes is real: Paladins have always looked like monster hunters and then bounced off actual monsters, because a Nemesis force weapon that wounds a high-Toughness target on 5s converts a terrifying attack profile into a disappointing one. Moving that to 4s is close to a fifty per cent increase in wounds on exactly the targets the army is themed around. Note also what the rule does not say: it names PALADIN SQUAD only, so Brotherhood Terminator Squads standing next to them gain nothing, and it is a fight rule, so it never touches shooting.