I got left with a bittersweet feeling after watching this. The potential for an amazing drama was there but for various reasons it didn't happen.
The first reason is the obvious, the actors change. I really liked the original one and really disliked In Woo. Nothing personal against him, I know it was hard being thrown straight into action on short notice, but even so, he is not that good, at least in historical movies (his performance in Mr Queen was equally poor). He might be suitable for a cheesy rom-com but not for this.
Second reason for me was the inconsistency in using Korean language. They have used some old pre-Joseon, some Joseon and quite a bit of contemporary vernacular which is very disappointing. All historical drama I've seen use pure Joseon language, nothing modern so for me it was upsetting (I am not Korean but I have studied Korean a lot). Next step would be to use the stupid konglish but I doubt they would do that.
Final reason was the quality of the palace intrigues, a lot of time very superficial and poorly written, felt like filler most of the times.
Now to the good parts. Best part is the cast, great main actors (minus In Woo), some really good supporting actors (minus a couple ajhussis who play in every drama and are quite poor despite the fact, must have good management company). So Hyun is stunning, which I already knew. I've never seen Yoo Hwa before, great job and what a stunning beauty, I was mesmerized .
The costumes are gorgeous, I hope they are accurate as they looked quite different from the Joseon era. Fighting scenes were good too.
The overall story was good, but could have been better, still I liked most of the actors so I have watched it pretty fast, was done in 2 weeks but only because I didn't want to binge-watch.
In conclusion, quite a mixed bag this drama . Still worth a watch.