Armin def agree with has been a giant disappointment. Legit outside of the main cast, Hange, Levi and Floche everyone died. That aint just a few deaths. Levi made the right call in terms of what was best for Erwin. It is ironic as soon as Armin ate Bertolt that's when he stopped taking W's given that Bertolt was a follower and never resembled a leader.
Along with Armin Mikassa is a character that also becomes more disappointing. S1 + S2 her character seemed interesting, but after the stuff with Kenny you would think they did more, but na
On another note, out of those that survived against the Beast Titan's rock pitch. It had to be Floche. And this dude was the ultimate lame. Much lamer then Eren at his worst moments. He turned into an annoying fukboy in S4.