I love it when Arcia plays well. I've always said I'd love to be wrong about him. I'll admit I was wrong about him. Mostly about his defense.
When you look at his expected stats, Arcia is pretty close to his preseason projections. He's basically been what was expected except with luck.
His defense has been the highlight though. I don't know if it's getting back at a position he's more comfortable at or getting to play everyday but his defense has way outstripped what I expected.
I will point out again that you thought his projections were off and should be lower/worse. So you were in fact wrong about both his offense and defense, you were just more wrong about his defense.