Bargie and Jiranee were the most forced at this event. Bargie have gotten distant and Bella is dating Weir, so these two were the most forced and awkward with each other. MK and NY, on the other hand, have always been this close. I'm not a fan of MK, but I didn't see any forcing or overdoing it between them. It may be hard to believe or accept, but MK and NY are naturally like this...which is one of the reasons why so many people adore them together. I think people who feel that MK/NY were overdoing it just have their own beef with them, and/or they're annoyed/tired of seeing them.
I'm not a big fan of koo jins myself, but I dislike how most people tend to look down on actors/actresses just because they do happen to have a koo jin. Having a koo jin doesn't automatically make one less of an actor/actress. Yes, it can prohibit an actor's growth, but it doesn't necessarily make them any worse than others who don't have a koo jin. Kim is one of the rare exceptions. She always manages to look and act well with anyone and everyone. In fact, many of Kim's fans aren't even MK fans.