It's a long review. I put a comment with spoiler with how the ending is not clear. There's so many endings you can take out of it.
FRUSTRATING ISSUES of the drama: Don't watch on Youtube. Subs are missing sometimes. Had to go to Viki for missing subs but the pacing is different from Youtube and I had to go back an episode on Viki.
The part that frustrated me was that I became too committed to this drama. I really wanted to make sure that I do not miss a single scene, so I watched the drama on both Youtube and Viki at the same time (since YT has 56 eps and Viki 55)
SCENES ISSUE- While watching both the YouTube and Viki version, I noticed that one site had the same scene in dark while the other was in daylight. After reading other reviews, it made sense. The editing team for this drama did a bad job on distinguishing day & night. Some scenes required night filters while others did not. It also made me understand why I was confused as to how some people saw Zhao Yao in broad daylight when she was supposed to be invisible.
The WORST part the editing team did to this drama is Episodes 51-end. The scenes were all over the place and not in sequential order. One episode's content was split amongst these 5 episodes. 51-55 is near the end and it was a critical point for the drama since that's when things are finally wrapping up and coming to an end, & their editing messed it up.
For Episodes 51-55, I watched APrincessofMars re-edit 50-55 and then Viki's 51-55. I see the ending they both aimed for.
As for the names issue some may have, I have no issue with it. This seems to be a pattern with Chinese historical fantasy/xianxia/wuxia genre. I've only watched TMOPB before this and it had the same issue. Characters name suddenly change and you're like confused for a bit till you understand who it is.

GOOD PARTS of the drama:
-The Acting. Especially Xu Kai and Bai Lu. I came to watch this drama after finishing AMA which made me come here for more. Xu Kai is not just a pretty face with a cute smile as some have said; his acting pulled off Chen Lan's devotion, sadness, sacrifice, and so on (you could see the emotion in his eyes). I find myself less attached to characters in general and whenever I do become emotionally attached, that's a sign that the character had an impact on me. When watching the last episode (of the fan edit), I was crying when he made his last sacrifice and what his last words were. Bai Lu did a wonderful job of showing the development of Zhao Yao's character. Shane Xiao also did a nice job by pulling off multiple characters. She had to act like Zhao Yao's demoness character and her own character of a shy, weak girl.
(Regarding Zhao Yao's character, I don't think they diminished her character. When she saved Mo Qing, she was strong, but was clear about her ambition. After becoming a demoness, while she helped people, she didn't do it in the way she originally envisioned, because she lost trust. While she was not in her full strength when looking like Zhi Yan, she still had her great martial art& sword skills. Chen Lan did save her a few times, but during that time they were building romance and try to clear Zhao Yao's misunderstanding of him and rebuilding her trust. They also had to make her realize that Chen Lan was making her original dream come true. Even though her character wasn't the same as the time she was a demoness, she was still strong. And also, when she regained her powers, she had her own battles. Chen Lan let her deal with Ming Xuan on her own and dealt with the phoenix instead. And when Chen Lan was abducted, she went to fight Ming Xuan again. She may have been helped a little, but she did most of the battle. Also strength of a character doesn't depend entirely on physical elements alone. You could see with how she saw through most of the traps set for Zhi Yan that Zhao Yao isn't a completely clueless character as the way Zhi Yan was painted. Zhao Yao also didn't fall for blackmail threats either.
- The Romance. The chemistry between the main couple is hooking. It was the main part of the drama that just kept me going despite there being so many issues with the editing.
- Some of the side characters and their stories (Qin Qian Xian & Shi Qi, Gu Han Guang & Shen Qian Jin, Sima Rong specifically)

What I DISLIKED about the drama:
- Crashing weddings. I didn't care so much about Zhao Yao sealing off Luo Ming Xuan on his wedding day cause he was such a hypocritical being and wanted to kill and killed innocent people. They did a thorough job of making you hate Su Ruo completely so you never felt sorry for her, even though she did evil things out of love and sexual frustration (literally what she expressed about regretting not being able to have sex on their marriage night). But what I was pissed about was our main couple. When they were discussing marriage proposal, I already predicted their wedding would crash, was hoping it wouldn't, but it did.
- How they tried to change Jiang Wu's character last minute and attempt to redeem him. Initially, I had no problems with Jiang Wu, but then he got on my nerves. At one point, Zhao Yao made it clear she likes Chen Lan, but he is still crazily obsessed over her. He crashes her wedding which was the start of me being pissed at this character. But then they try to make him to a good guy who saved Zhao Yao with his heart. BUT THEN he stabs Chen Lan with the Liutenhiayi Sword causing Chen Lan problems. THEN he tries to provoke Chen Lan KNOWING that he has an inner demon and cannot control it. He PURPOSELY made him jealous and causes his own friend's death. But he blames it entirely on Chen Lan and asks for a life in return and kills Ah Da. And they try to redeem him by showing him "sacrificing" himself and then being Zhao Yao's sword against Ming Xuan. If they wanted to redeem him, then they should have made his character less irritating. But his crimes are on the same level of Su Ruo.
- Lin Zi Yu. Her character is worthless in the drama. Should have been deleted.Or they could have just made her the male character from novel.
- Repetition of Chen Lan riding the dragon with his eyes closed. Repetition of same flashbacks.
- Killing off people that are in relationships. I felt like this drama had this repetitive theme. While Zhao Yao & Mo Qing don't start off officially as a couple, they kill her off for 5 years leaving Mo Qing heartbroken and then develop their romance. Then you see Rong's lover Yue Zhu getting killed. Then when Gu Hanguang and Shen Qian Jin come into the story, I was expecting to see Qian Jin to die when she has the Cold Poison taken over her. And at this point, I theorized the drama is killing off all the women in the couples. But nope! They kill off Gu Han Guang. They crush your hopes of a Qin Qian Xian & Shi Qi couple. Why even bother trying to develop romance between them if you're just going to kill them off?
- The ending. Even if I understood both fan re-edit and Viki's ending.. Viki version.. they couldn't do a proper job making it continuous. And make the costumes match. But this is the drama's team fault.
- UNEXPLAINED events in the story which also led to plotholes
- Zhi Yan's weak character. She acted it nice, but sometimes I was annoyed at how clueless and weak they made her look at the start.

Overall, even though it seems like I have more complaints, I still can't say I hated the drama. I did find somewhere about the differences between the novel and drama. I'd say the novel cut down unnecessary love triangles and fillers. Better explanations. Had a better and happy ending that the drama failed to deliver. I think some parts of the drama that weren't in the novel were fine while I also wished they included some parts of the novel such as the ending and less killing of relationships.
If I were to re-watch, it would just be for the romance of the main couple and scenes with my favorite side characters. Everything else I'd skip.