God is love. God is just. God is merciful.

[Aoi Magi]

That's the point of the cross. The judge paid the just penalty himself, which allows him to be merciful as well.

You'll likely complain that it's not just to allow one person to pay the penalty for another. That's fine as your opinion. God sees it otherwise, and as lawmaker and judge it's his opinion that counts.

1) He orchestrated the crime, he sanctioned the punishment, he determined the penalty, he paid that penalty, to himself.
- Sounds more like a psycho dictator to me.

2) I'd actually complain he didn't pay the penalty. If you pay the officer for your speeding ticket, and then snatch the money back from him, that's not paying the penalty. Similarly, JC didn't stay dead, he played possum for three days then flew away.

3) How do you know God is the lord and judge? And how do you know there's no one above him? As far as I know, YHWH is or rather was a lower member of an ancient pantheon of other gods.