You´re right, with so many people sharing the screen time, Luhan of course gets limited exposure. Personally, I´ve come to like the show and the cast to such a degree that I will watch the whole thing, not just Luhan´s parts ( though he´s still the main reason I watch the show, I probably would not watch it if Luhan wasn´t on it). Although, during the last season he did get quite a lot of screen time, but a lot of it was through his interactions with Dili Reba. Since they obviously can´t push that ship anymore, I don´t know if he´ll get less screen time the upcoming season... Still hopes he´ll stay on Keep Running, as you say it contributes in keeping the cast relevant – and as we concluded; he likes it.
Something I do wish to happen, if he stays on the show, is the thing they talked about in episode 13 – that the members should all invite their lovers as guests for one episode (so that Guan Xiaotong can be on the show again, https://onehallyu.com//public/style_emot...).
Ah yes, that would be interesting to see..(although gathering fbb, hxm, sun li in 1 episode might be difficult)