You misunderstand the purpose of the Father's punishments of his children in this life. You're right that God, as a good father to his children, doesn't seek reasons to stomp mud holes in our butts. His punishment goal is to correct our actions, not to extract revenge for our past errors. He loves us so he only punishes us enough to get our attention and change our heart; if we recognise our errors and get things right without punishment then no temporal punishment is needed. Meaning WE determine if we get punished, and by how much; I don't think that's a bad system.
Okay, let's use our heads and think a bit. Can we actually believe the meanings of scripture? I think so.God wants us to think! Why else would He have given us a brain so capable of abstract thought and investigation???? Sometimes, I have to wonder how we got so averse to actual logical thinking and evaluation!
First, in Prov 3:12, Acts 17:11 and Heb 12:6-10 we're plainly told that God WILL chastize his wayward children BECAUSE he loves us, he's not a tyrant venting rage. So, we are left ONLY with the questions of where, when and IF we misbehave without repentance but God doesn't chasize us then he doesn't love us as a father and the Bible has lied; neither of us believe that. And, we also know that in the after life, all temporal punishments are passed over as if our errors never happened, right?
So, as my head sees it, and by elimination of the other two possible options, God's promised correctional punishments to discipline each of his beloved children has to occur here, before mortal death. How can it be otherwise?
Now, please note that I haven't even suggested that we will be whipped down or humiliated by God everytime we stumble. Those who foolishly think every bad thing that happens to us is automatically a "punishment" from God for our occasional failures are very wrong and need to read (and try to understand) the book of Job.