It's not that bad or to good, it's an average drama.

1. ML- nothing bad regarding ML character.

2. FL- I have read comments of issues regarding the FL, yes, some were practical & some were illogical. When she broke up with ML 8 years ago, she broke up with telling the reason, from her perspective it may be only choice, because if ML give ups his dream for her than she may guilty for her whole life.
On the other hand, if she have told him the situation she is in now, he might have found the solution for the problem.
So it's difficult to say whether she is right or wrong in this.

3. ShaSha (FL cousin sister)- For me ShaSha's character, dialogues, reasons were illogical from start to end, FL was much better.

4. AI development shown in medical device & AI development in technology in sign language, I loved this that.

5. But the drama's main concept was on communication tool, which is just a communication tool, which is required for just only communication, & what is the need of emotion, feeling in a tool which is just a communication tool.

And mainly where AI & technology are developing, the mobile brands technology, features have developed so much & still it's developing, so mobile brands will install software in their mobiles & they will develop this software day by day & people will get this software installed on their mobile for free, why people will buy extra device only for translation purpose.

6. The writers decided to show that ML & FL was married & skip their ceremony. ShaSha & Wei Tian wedding ceremony was shown & it's good, but after they went for medical help, what happen there & how they got back together, everything was skipped & directly their wedding ceremony was shown.