I liked it.
What's wrong with the Devil wanting to repent?
Nothing.
It's more the angels getting on his case for nothing, when they're basically jerks themselves. (Which is what I mean by tyical tv writing.. The religious icons are blatant arseholes, while the villains are saints.)
Another thing is the logic on why they hate Lucifer. The comic book versions basically had it as angels = facists, devil = anarchist, but both were neutral to humanity. The conflict between devils and angels was that angels supported a grand design, while the devil wanted freedom to do as he wishes. Humans could die from either sides actions/inactions (For example, a somewhat related story had Spectre, who's job is to punish killers, genocide an entire nation caught in civil war. Archangel Michael, the brother to Lucifer, called this just.)
But here on this show, I'm not seeing why the angels hate Lucifer. He was criticised for breaking the balance by being merciful? As in, helping humans? Yet, the angels themselves don't really help humans either, so where's the balance being broken?