I think it's too soon to tell, frankly, but it's clear that we're being presented with something more than "he's a bad guy who needs to be ganked." As much as I want to hate him, I don't feel like I understand him well enough.

What I'm curious about (and will have to re-watch the ep) is are they saying that Gadreel just let Lucifer in (since Show is evidently going with the Miltonic Fall) or that he was tricked--with the implication that he should have known better? If so it seems kind of hypocritical for Cas to be so rigid when he's given absolution to Sam and Dean, who have both been tricked in the past.

I think it's an interest mix of characters and storylines going on now and I just hope the writers follow through with it.