I have been enjoying the current season of 1N2D.
Initially, I never thought the team would survive another round of five people. The new PD, a former junior producer from the first two seasons of the program, is back, and initially, Kim Jong Min thought that he could bully him... but it hasn't been the case at the moment.
So Youn Jung Hoon and Dindin have improved for me in the current setup because they are actually speaking out and just for the sake of instigating chaos against the members and the staff.
Dindin has always been mischievous, but most of his interactions are forced to the point that he was once seen as the unfunny, trying-hard character. In some ways, he is positioning himself as the smart-but-devious guy, and just in like in the airport episode, this character is making him watchable. The same can be said with Jung Hoon - because if Bang PD made him the old matinee idol in the mold of Cha Tae Hyun, he is embracing that character archetype of Kim C. Jung Hoon doesn't need jokes but he needs situations wherein his star power can transcend. I think next to Jong Min, he has the most star power, especially with the ladies and you just can't make him the background character.
Na In Woo's dialed down on his overzealousness and prankster persona and I'm kind of loving his current "accomplice" gimmick (he'll still do well in challenges but he's not going to stop the troublemakers from stirring up trouble). Moon Se Yoon isn't trying to be the main character of the show and he is doing well in the process. He is acting like a dialed-down version of Kang Ho Dong - which was something that Defconn couldn't get in the third season.
And in Season 4.5, Kim Jong Min has finally taken over the leadership duties. In their current situation, Jong Min is the most popular and the most approachable member, especially in places they need to interact with people. Jong Min also knows all the ins and outs of the program so as much as he's the bumbling idiot, he can at least try a bunch of things to help a situation.
The yoga part in the second part of the Jeju for instance gave the members a chance to tease Jong Min's non-existent marital status. The episode also made him the de facto ace by casting Lee Hyo Ri.
Also in the embarrassing "nap in front of everyone" mission, Jong Min is the one interacting with the crowd as if he's a festival host. I think in the past few years and judging from the programs I have seen him in, he is transitioning from "village idiot" to "accidental leader... but still an idiot" and it's working for him.
Anyway, I love the current setup of the season and if and when a sixth member comes in, I expect the rest of the members to inflict all the war shock they have been experiencing on the said member - and it will be awesome.