the eren and the armin are only interested in shipping with each other so that drags both of them down as the worst, and i agree with you on jean, they're definitely being dumbed down and the player seems more interested in being funny than being in character

everyone else i don't have much of an opinion on but i really like the levi and don't see how they're ooc so not sure what you mean by actions spoiling the character since he's been in for a few months now. it still reads as him to me. erwin i would say is about average and they could stand to be a little more active but ymmv with these leader types, i find they generally attract a lot of flakes sadly.

tl;dr one of the better casts in the game but not without their own problems. could be better, as you said, but i like them well enough.