Going into the drama, I watched it without putting too much thought. Only after reading comments online did I see the controversy, but I will not talk about the controversies (the age gap/cultural appropriation). I'll let the viewer watch it and form their own opinion.

Pros:
1. Great cast. The only reason I finished the show was for JiChangWook and KYJ. Both are very attractive and good (or capable at the very least) at acting their roles/characters in my opinion. Supporting characters were okay, I don't have any strong opinions on them.
2. If you like slow burn romances, then this show is for you. But, I warn you, there is not much romance.
3. I will give it a +1 since this drama has the FL liking the ML first, and them making moves.

Cons:
1. No skinship. I don't really recall hand holding. There were a few hugs, but there is no kiss scene. Ending is a teaser kiss but they don't actually kiss. I still don't know why they butcher the ending like that when this is a romcom. Yes there is kiss scene in episode 1 but for the sake of the development I don't classify that as a kiss scene.
2. The drama could have been better if there was no kiss scene in the beginning, and they saved that for episode 9 or 10 or something. Yes, I get that it may follow the web toon but hey not everything needs to be followed right? We can make some adjustments for the sake of it being a drama? Right?
3. The ML is involved with his ex for like a majority of the show. Way too much time invested with his ex when the show needs to develop and move on. If I remember correctly, his ex is still in his life around ep9. And even up till the last episode the ex is still trying to get back with ML... isn't this a tad bit too much?
4. Too much attention/emphasis with the parents. The drama does not give enough attention and screen time to the couple. I wouldn't even call them a couple, but yeah. They need more conversations together. They really don't have much to talk about, now that I look back and think about it. It's mostly them just laughing or ML making some joke on how he's awesome and FL praying that ML makes a move. I don't mind this though, I only mind the emphasis on the side characters and family.
5. Most of the show is just the FL hoping the ML likes her (dont get me wrong I love it when the female makes a move on the male first), but its so repetitive to the point that it gets boring. It's to the point where as the viewer I just wish the ML just accepts her advances, but throughout the show its just the same repeating process. I am talking about the times AFTER the ML has broken up of course.
Here's where it gets interesting.
When the ML finally proposes to the FL, guess what? The FL pulls a 360 and says she needs to think about it... when she has been madly* in love with the ML since before ep1. At this point the director could have gave a classic kiss scene. But hey I understand not every drama needs a kiss scene for romance right? They could have even just done some cliche romantic talk scene but no. They just further complicate by having the FL be undecisive then run away.

TLDR: Beginning episodes were pretty good. Stayed for the cast. Plot and development were not good. Cast was eye candy, probably the only reason to watch. Not a very satisfying drama.