my jumbled epiphany

Following are some jumbled thoughts as I read about Bonhoeffer and "religionless Christianity."
Bonhoeffer's central point was not religionless Christianity, but rather "who is Christ for us today?" One of the things that Bonhoeffer then asked (there were three things) was how should we live in a "world come of age?"

A world in which God is "dead" is good because it forces Christians to not rely on a powerful version of God created by institutional, religious Christianity, but to instead look to the cross, where Christ became weak and powerless. His humility and powerlessness is where true strength lies.

Bonhoeffer's "a world come of age" refers to a world that has no scientific need for God anymore. Religion has been forced to only questions of eternal significance now (e.g. where will I go when I die?) What if that too can be explained without God? What then? Thus Bonhoeffer urges Christians to live as if God is dead. He even claims that God wants us to live as if he is absent from the world, because that is exactly what directs our attention to the cross. "My God, my God, why have you forsaken me?"

In some ways, this seems a rather large theological leap - to go from that one quote about God forsaking Jesus on the cross to God forsaking the whole world. And yet, something rings true about it. Verses like "strength made perfect in weakness" come to mind. Christ taking the form of a servant. He didn't come as a powerful king. He came as a weak servant.

Furthermore, Bonhoeffer is arguing that the religious Christianity's God is a human construction. A powerful God who rules from afar is not the God of Scripture at all. Only in a religionless world does the powerful far off God die so that we are able to see the God who came to this world and still lives in this world, among the weak and suffering.

Wow.

Mind. blown.

Hmm...suddenly the Bonhoeffer of Letters and Papers from Prison makes a lot more sense.

Questions:
How do I reconcile the God of the OT with this - a powerful, wrathful God - certainly one to whom the Psalmists prayed for deliverance and vengeance?