I don't know if I called them suckers, but the expat 737 FOs aren't making 9000 a month, they're making 6x00 a month, only have 9 hard days off, 3 "soft" (commuting) days, and there is no way they're gonna have a chance to upgrade or transition into anything bigger/better becuase the KAL union won't allow it. There's one thing bringing in ex-pat captains with a lot of command experience in type, but Korean Air won't waste the time and effort upgrading and/or transitioning expat FOs. If they did that, most would leave after a couple years having the type and a couple thousand hours command under their belt and not finish the contract, and Korean Air ain't that dumb. So if growth and/or upward movement is something you value, then Korean Air is not where you want to go. If you're furloughed and just need a job though, then this is better than nothing.
And if any of the contract agencies say there is a potential for upgrade and/or transition, they are just blowing smoke up your APU becuase they want you to sign with them. Ain't gonna happen. Korean Air's union actually has some teeth, unlike the pathetic attempt of a union Asiana has.