First of all, I did not read the novel or watch the anime, so this is my impression from the drama itself, regardless of how faithful it was to the source material.
Overall I'm really impressed with it. It's not perfect, there are definitely things they could improve on, but on the whole I got the impression that there was a lot of work and thought put into the production.
I liked the general idea of this. It is a very cliché plot, sure, but in a good way. I really like characters like TS and the whole "chosen hero to change the world" thing feels nostalgic in a way.
I liked the pacing and the world building. For someone like me - with no preconceived knowledge - they did the introductory part really well. It was organic and built into the story, instead of a long boring lecture that I usually tune out after two sentences. The story sucked me in from the very beginning and kept me interested until the end. I did not skip a single scene and might even rewatch this when I have the time.
There's a lot of humor, it fit really well. Master and Headmaster are the best comedic duo in the c-drama, I've seen.
The characters are all written well, I understood their motivations (with few exceptions) and relationship development worked for me. There was only one exception: Tang San and Xiao Wu. I had no problems with XW as a character, yes she's childish, but it works for her and I didn't find her annoying. But they kind of went from "Hi" to "I will die for you" too fast, IMO. I didn't feel it. The rest of their relationship worked for me well enough. I do think Dai Mu Bai and Zhu Zhu Qing have a much more natural progression.
The acting is good, no one felt overexaggerated or fake. Acting is rarely a problem in c-dramas, so I have nothing more to say about it.
The CGI here is great. Can it be better? Sure. Are you watching a Hollywood movie? No. Some parts could be improved, but overall it looked like a part of the world, not like some cheap animation inserted into it. The CGI parts of the fights were always great.
The fights themselves, though... It was pretty good in the beginning, when there's hand to hand, but as soon as we get to fights with Marital souls, they flop. The fights (with the exception of the one in the last episode) lack action and end too abruptly, characters just stand around a lot waiting for something to happen.
And speaking of abrupt endings, some scenes are cut so weirdly. There's like a moment of anticipation and then we cut to the next scene and it turns out everything has ended. Sometimes it works, but sometimes it just "hey, what happened here?!".
I didn't have any problems with BGM, I didn't notice it. With one exception: XZ's song. And don't get me wrong, I love the song itself, but it seems like it was recorded after the fact and inserted into the scenes also after the fact, without much care whether it fits or not. The first time, worked ok, but the other two... there are people talking! Why are you adding a loud song with lyrics in the middle of the conversation? *facepalm*
I think, I can talk for hours, but without spoilers those are probably the most important parts. If you are still reading this (doubtful), then definitely give this a chance it's a very light easy to watch drama. All the things that I didn't like are minor and don't spoil the overall impression.