Yea, I've always envisioned this as a full piece, and honestly wrote it as such, so I think that plays into some of the "story" bits not feeling quite there yet, since admittedly a lot of that is backloaded. The front bit is more character work, the back bit is more story.
As far as the MC goes... there's a lot of things going on here. First, you're right. His life is "boring". That's partially by design, although I definitely see the whole "Man his life is boring when he's not interacting with people" thing. That's part of the reason I've started peppering in his backstory a bit, I did a small piece of it in CH4, another will come in ch5, plus as CH5 comes he'll have more to do, so hopefully that'll be slightly addressed. Or not, who knows.
Regarding your other points: #1, it's funny. All the character backstories I had written on day 1, and how (or if) they knew each other. So far you've mostly had characters who DO have history interacting (Like erin/nikki). Ch5 brings a lot of character interactions between people who lack that history, and don't actually know each other very well, so that's been very interesting to write, and I'm looking forward to putting all of that together.
Regarding #2... It's actually not much work. The hardest bit, is the coding side of it - making sure all the variables are in the correct place, and trying to make sure things are coded properly to take you on the correct path. The writing side of it, for me, is easy. Idk why, but it is. Who knows. Probably because I'm a halfway decent writer, (but a piss poor artist!) who has a mind for those sort of details, if I had to guess.
So why don't I have much support? Honestly? I think it's because it's just not that great. I have a decent story on my hands, and it'll be better IMO once it's fully realized, and fairly good character work I think, but I think if I have to step away from myself and be objective, it's just not that good right now as a whole. I can say with honesty it's not as good as I wanted it to be when I started.
I've slowly come to this conclusion over the last week or two, and tbh, it's sort of destroyed any motivation I've had to work on the game. All the work I've gotten done, has been basically me forcing myself to do it, because the motivation just didn't exist. Add to that some pretty harsh (Not necessarily undeserved, but definitely harsh) criticism I've gotten recently, and my motivation is at an all time low. A big part of me says "Not many people like this, and even less like it enough to support it, so why waste your time", and that has become increasingly difficult to fight against.
I'm still absolutely fucking determined to finish this, but it'll probably delay the release by a week or two while I fight to get myself motivated again. Don't get me wrong, I'm not looking for reassurances or anything, just randomly kvetching mostly, eventually I'll fight through and find myself in a spot where I'm motivated again, but for now I'll just have to find a way to deal with the honest realization that, what I've produced, is not as good as what I originally envisioned. I think what I'll need to do first is take some time and figure out where that disconnect occured - then I'll probably be able to get into a spot where I'll be excited to work again.