Yeah I'm in the minority with that lol. I like taking my time and working out strategies to take down any given area. With co-op it's just run and gun... I don't really see the fun in that. I love to take my time with it and look everywhere. Explore the entire map to try to find hidden chests or whatever.
Joshi, I haven't heard of that. I never use the skins so I don't think it would affect me. I sell all of those I get.
I do play Co-Op, but I am a completionist and want to do much of the stuff you described as well. I have people rushing me to beat Jack, and I'm still doing side missions and leveling an alt as well with someone. But I will possibly finish it tomorrow, since the Pirate DLC is due on Tuesday.
You should play it with me and you could get free xp exploring while I blow faces off people with my talking corrosion sniper rifle that accuses me of being a terrible shot, stealing ammo from kids, and supporting slavery. Gun rocks