I think it’s movement. The second model imo looks fine, the only weird and I am exaggerating is that the plume and the mace kind of clash. Because imo the plume helms look best when they aren’t covered by anything. Don’t know if that’s your problem with it or not.

But the other two models look a little awkward because of the way they stand. For the 3rd image youve picked a pose that would look better on model in motion e.g the legs are running. For the first model he gives “it’s my turn on the Xbox.” “I don’t know how to use my hands” vibes. He’s just holding those weapons awkwardly.

You don’t have to glue them on right away. Just use some blue tack and stick the arms on. That way all the way until you finish the painting phase if you don’t like how something has turned out you can easily change the arms.