Expat FO's get treated the almost the same with Korean Captains as they do with expats except the expat Captain will use a little synergy and the Korean Captain thinks it all them. Theres not much in the way of conversation with the former but the Korean Captains (most) are easy to get alone with. You land about twice a month or sometime less. Most of the time the Captain will do the out station legs and fo's will land back in Incheon. Some Korean Captains will ride the controls on you from time to time but considering the experience from local F/O's they may have reason.
Korean is under a big change with all the expats coming to fly there and from what I hear from the past, its getting better. You have to put your ego in a box and leave it there till you get home. If you cant do that your going to have problems.
You have to look at Korean (for FO's) as a place to make good money and have a great home leave, and thats about it till something else comes along. Lots of Jeju guys who dont have the schedule expats do are leaving for other companies in droves. After years of abuse you cant blame them. Its not a career path you come to Korean as any fo (except military), its a quick fix..for now who knows what the future will bring.
As for the upgrade for expat FO's. I doubt it very much, though opinions vary.