Seo In Guk won over hearts with his complete puppy dog look and sweet personality in the drama. He was like a lost dog trailing behind his owner while shooting her apologetic puppy dog eyes the whole time. He did an amazing job, but how might it be if Seo Kang Jun had been given the role instead? He also has puppy dog eyes, especially when his hair is wavy (like in 'Cheese in the Trap'), and a cute pout that could win over hearts in a second. Plus it'd be a cute way for him to get Nam Ji Hyun this time around after failing to do so in 'What's With This Family.' For me, I loved Seo In Guk in the drama, though, so no complaints here!

Han Hyo Joo got a lot of hate for her portrayal of the flighty and cute character. People criticized her for overreacting to everything in a comical way, so I can't help wondering how Hwang Jung Eum would have done in the same scenario. She's known for her comedic, exaggerated reactions, but unlike Han Hyo Joo, she's applauded for it because she does a good job at not coming off too cringeworthy. She also doesn't care about visuals, making weird facial expressions to up the comedy, making everything seem a lot more natural and less burdensome for viewers, so she may actually have done a better job than Han Hyo Joo, who isn't used to this kind of comic acting and seemed like she was the one who had jumped out of a comic strip.

I'm siding with the viewers who find Kim Go Eun's acting in the drama a bit forced and unnatural, like she's trying too hard to be a cute, endearing teenager so she ends up seeming more like a 12 year old. Having said that, I wonder how it would have been if Baek Jin hee played her role in 'Goblin.' Like Kim Go Eun, she has a unique, plain-yet-beautiful look and is absolutely adorable when she smiles. I think her playing the role would have been more charming because she really has a natural childlike sweetness to her (think from her 'High Kick' days), so she wouldn't come off as trying too hard. Kim Go Eun looks young but naturally radiates a mature vibe. She's trying hard to silence that part of herself through her acting chops, but it isn't really working. For me, it's hard to buy into the act, basically. Baek Jin Hee is good at acting in melodramas, so she'd portray the pains of the character well when necessary, as well, and has done mature roles in the past if there are indeed time lapses.

Don't get me wrong, Lee Jun Ki was perfect for his role, like Seo In Guk was perfect for 'Shopping King Louie,' but I wonder how it would have been if Kim Nam Gil had taken the role instead. After all, he did the whole sexy, angsty bit in a historical drama first through 'Queen Seon Duk' in which he absolutely shined and got immense recognition as Bidam. He played the bloodthirsty but lonely warrior before, so he would have done a good job here, too, while also showing some new charms because he's a talented and versatile actor. He rocked that long side-bang look, too. Unlike Lee Jun Ki, he gives off less of a cleancut elegance and more of a rough-and-tumble, rawly manly vibe, which would have been an interesting take on the character. He might have made the drama a tinge darker with his aura.

Gong Yoo is doing a pretty good job acting as a supernatural being in 'Goblin,' so he seems like he'd do a good job playing an extraterrestrial with magical abilities in 'You Who Came From the Stars.' His character is both stoic and endearing in 'Goblin,' after all, just like Kim Soo Hyun's character. Also, with his tall height and mature looks, he'd look great paired off with Jun Ji Hyun. The qualms I had with Kim Soo Hyun was that he just looked so young and sort of scrawny because of his lean figure and small face next to his tall co-star with her overpowering presence that it seemed like Jun Ji Hyun could just eat him up. I think Gong Yoo could lend a more masculine, mature air to the drama while keeping things lighthearted and sweet.

There was some controversy over YoonA's acting in 'The K2,' but some people believed her portrayal of a delicate damsel-in-distress and hysterical-at-times-angry-at-others hostage was well done. Although appearance-wise, Park Shin Hye is quite different, she may very well do a good job at this, too. She played a character in 'Flower Boy Next Door' who was mostly vulnerable and sweet but expressed righteous and justified anger toward a friend who betrayed her cruelly. In 'You're Beautiful,' she played the childlike and innocent character. In 'Doctors,' she partook in some action scenes. If she combined her experience from those roles, she might have done a great job at playing YoonA's character in 'The K2'!