It's nice to see some forward movement, and it's mostly thanks to one character.
drinking alcohol - even if he did spit it out.
Eren seemingly turned on Mikasa? Frustration over the way she condescends to him finally breaking out? Indications that his control over the titan he's able to summon is erratic? As usual Isayama isn't giving us much to work with in terms of hard evidence, but it seems very likely to tease yet another major layer of the mythology that's going to be important in the long run (and with AoT it promises to be a very long run). We've spent 7 eps just on Trost already, and it seems as if only now is the real importance of the event starting to come into play.