The whole idea of switching two brides to be, of people with a double identity, of a couple from different social statuses, of solving crimes, uncovering past wrongs & identities, of atonement, of a wholesome friendship between couples and of them saving the world... is of course nice but you might notice, a bit full as well. Or, it would have have to be implemented in a way more clever way to make sense and be satisfactory.

There were just too many storylines and they didn't bring them to a good end or if there were, most were rather shallow. Basically a description for the whole show, it was really shallow. That's why I wrote it is a no brainer and you might enjoy depending on what you are currently craving.

I sometimes had the feeling, that the writers placed this story originally in a modern world and then switched to period drama in-between. I never had the feeling that they really tried to portray a story in the past. The actors were just wearing nice costumes to underline the story but did not necessarily adhere to any rules from "the past" - like they never really are really accurate but this was like they didn't even try XD

The fighting scenes were ok to nice.
There were a lot of filling in episodes which could've been used for other things. e.g. character development.

And yes, the female leads characteristics were nonsensical as well. Again like the writers started of with a strong independent female lead and then decided "naah, let's make her childish, dumb and euh... weak". But, as good as the male lead might've looked, he also had no real character.

The actors made the best out of this. They at least portrayed convincingly what they were supposed to be.
The last 5 episodes were the best :D