It is similar because Sungkyunkwan Scandal is the what In a Class of Her Own is based off, so if you enjoyed it, you might wanna check out the original which follows pretty much the same plot.

Both take place in a comic book universe, and both are supporting character or extra's for the story, that want to change their ending for the better

They are similar in the aspect of how at least one of the main characters I actually from a comic book, and they both have some of the sweetest romances. The only major difference (well there are many) I can think of is that in Extra-Ordinary You for most of the show the characters not go to different universes instead they are known to the fact they are in a comic book, while in W they can like move from both worlds to get to the other.

It's similar in the aspect of like story, but when you watch Playful you will automatically think of the lead from Goong because they are quite similar a well as the fact they are written by the same screenwriter so if you enjoyed Goong you most likely will enjoy Playful Kiss, you will also have the teddy bears at the end of each episode.