About the line distribution, I personally trust in bts members and producers decisions. I mean, they're a team after all and ultimately it's their choice to discuss and decide. Fans voicing their opinions are fine of course, but the line distribution isn't going to be equal all the time, someone's always going to get the short stick.
Jin is my bias and of course I would like to see him get more opportunities and lines, but I don't think it is our place to say what should happen in bts' music decisions. It's up to Jin and bts, and their music producers to discuss and decide. Ultimately, what comes out consists of all their hardwork. So I would much prefer it if people chose to appreciate what they put out instead of having these recurring debates.