Yes, the ultimate justice you point out is the balance. Also, in that list of bad things, slavery is down considerably, but it seems we have enough murder, incest (child abuse), polygamy (Muslims, LDS) and racism to go around. We have the likes of the "Islamic State," disgusting as ever and not likely to have a PBS cooking show anytime soon. I mean, check out the news: you want to hear from disgusting? Then there's the question as to when mankind, with wills of our own God does not compel, ever collectively repented, to date, seeking righteousness and the Lord in all our affairs, rejecting the ways of sin, vanity and Satan? You ask why God this and that, well, why man this and that? Who's really the problem? Who has the rules and can't get their act together? I fail to see the world, with respect to sin, is markedly better. Maybe we've exchanged most of the slavery for promoting homosexuality, for instance, but sin is sin, with respect to a completely holy God. God is long suffering, but read Revelation if you believe justice is not coming, for one and all. And if He put to rights man of the Old Testament, it would have been lights out, and we'd never have had a chance to repent, come to the Lord Jesus in faith and have eternal life in His kingdom.
Romans 9:22-24 What if God, willing to shew his wrath, and to make his power known, endured with much longsuffering the vessels of wrath fitted to destruction: and that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory, even us, whom he hath called, not of the Jews only, but also of the Gentiles?
2 Peter 3:9 The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance.