My own opinion, which is worth nothing, is they are both improvements but at the same time both missed the mark and for the same reason: color.
The Kings would have been better served to go with purple as a primary, They could have coupled that with silver and black to avoid the overlap with the Lakers. Like I said, they are better than what they replace, but they also go back to a time of "great, another Raider knockoff."
Ducks would have been better off going with darker pants. Replace black with their original eggplant and use that for the pants.
BTW, I normally like the contrast shoulder yokes give, but the orange ones on the white jerseys create orange overload. Maybe the orange theme will look better on the ice, who knows?