So Running Man introduced this idea of having interim members.
Through the years, the show's fans have had polarizing thoughts regarding new additions Yang Se Chan and Jeon So Min. I guess this is what drove So Min away. Some fans are also angsty with Song Ji Hyo.
Let's face it - it's hard to act all cute, even if you are if you are pushing 43.
And poor Se Chan has been doomed in a spot where he can't do anything right. He was seen by many as Kang Gary 2.0, Monday Couple 2.0 (his unusual dynamic with So Min,) and even the baby version of Lee Kwang Soo and Haha. Even if Se Chan has progressed as an entertainer, he can't shake off the fact that compared to the other Runners, he is just... there.
Enter Kang Hoon.
He is known as a versatile actor at 32 and had his first variety show credit as one of the members of Express Delivery Mongolia Edition alongside RM mainstay Kim Jong Kook. He got the nod to do the show because of his first Running Man appearance. In six appearances in total, Kang Hoon has been good. The interim member tag may be credited to Lizzy, although she was officially a member in its early stages, because of her brief stint. With that said, she's rarely talked about as compared to Kwang Soo, Gary, So Min, and Song Joong Ki. The perks of the interim tag are that a person can come and go anytime with little to no burden but at the same time, this is Running Man we're talking about. I am a Hong Jin Ho fan, but I don't think Jin Ho, Joo Woo Jae, Kim Dong Hyun, and Cho Sae Ho have enough firepower to become the seventh member. If RM was able to snub Lee Sang Yeob, Lee Mi Joo, and Kang Han Na, then only an actor or a top girl group member could join their ensemble.
I don't see Kang Hoon as So Min's replacement. He fits more as Kwang Soo trapped in Kim Seon Ho's variety mindset. Hopefully, we see a female interim member like Shin Ye Eun or Kwon Eun Bi joining the cast. Unless they do group missions with a female guest, Ji Hyo just sticks out like a sore thumb as she is less than an "ace" now, she has no loveline, and she always lets the female guests shine.