I didn't really pay attention to any solo work any of the others did, besides JH (and YG of course, already have shared my thoughts here about that album). I gave JH's album a couple listens, and at the time when it came out, I liked it. Now however, I'm bored of it. The album did get a lot of attention early on, and sustained that attention for a while, even though promotions weren't that plentiful and people eventually stopped talking about the album a few months later. But aside from YG and J!n, there isn't continuous talk about any of the solo work a few months after release. I'm sure that it will be the same for Tae and JK as time goes on.
And I really, really did think that if Tae released a solo album, that because he's the most popular member, the album would explode in popularity regardless of quality. But nope, that didn't happen. Pretty much everyone seems to have forgotten it. Even a friend of mine who likes Tae a lot, doesn't talk about his solo album anymore. And it's funny to me that his own fans aren't going bonkers for him, given that a couple years ago fans were begging to Tae and JK to release solo albums. There was a huge amount of speculation about what their albums would be about, when they'd be released, all over twitter and tumblr. And now it is radio silence.
In regard to YG as a host or music producer... Producer yes, absolutely. Host? No. I tried to watch the RM episode of his variety show and I was so bored a few minutes in and clicked off. Tried to watch a non-BTS interview he did and again, BORING. This variety show is an excuse for YG to drink and to get a chance to talk to his fave people, and basically boast about the special people he knows. That doesn't mean I don't think he respects the people he's interviewed, but I do think there's a level of ego-inflation in the variety show and concerts as well.
What I'll say is this: The variety show is meh, but, it plays to the Korean audience. Combined with his ability to collaborate with other musicians and produce songs for them, his own music which is consistent across all his mixtapes/albums, his charity work, doing commercials, producing music for brands, modeling for V@lentino, the NBA sponsorship, and overall well-rounded behavior, he is showing he's capable of having a K-pop oriented career. He is showing he can exist outside of BT5 and is marketable. He generally looks "good", not good as in behaving like an angel, but good in terms of what Koreans expect from an idol. He has never branched into acting, and I doubt he will, but he probably could get away with not acting beyond the occasional commercial. So yeah, as much as I think the variety show sucks, it is helping his career at least.