Comments are weird, who is forcing audience to accept Jisoo as a good actress? It's her second drama ao ofcourse she wouldn't be as good as he age fellows but she is really hard working so I hope she'd keep improving but if you're convinced that she'll not be a good actress and you have no other reason to watch the drama then just skip the drama.
Besides being undercover agent in school/college nothing is same. Main Hoon Na had completely different storyline like illegitimate son, stepmother, protecting stepbrother and re-uniting with stepmother and even indo-pak relationship. Nothing is same.
When I saw actress's age I thought it's big age difference but then I remembered Rowoon is also just 28 lol. Sometimes I forget that he is still in 20's.
King of... comedy? Who are you thinking about, and which comedy? That's the type of comment an AI would generate.
Regarding comedy I think he has given some of the best comedy dramas like Our beloved summer, Rooftop Prince, Fight for my way, The boy next door, Ho Goo's first love and many more that I've not seen. What more do you need?