I don't know if anyone has talked about it, as it is really easy to miss, but we actually have confirmation that shields are returning - but this time they can be equipped alongside weapons. It is the item Ignatz steals from Dedue here. The shield on Dedue's map model even changes after Ignatz steals it. It is hard to see, but Ignatz actually equips the shield as well, but I don't see his model change at all. Maybe only classes that have shields on their models normally get different shield looks for equipping them?
Also we get to see Dedue as a "third army" unit. Canon classes are also a confirmed thing - which makes sense given other house students may/will be enemies post-time skip.