Assuming your highlight of the last 1/3 is an accurate summary, it still doesn't help much. No doubt we can agree with the proposition that "understanding hell" helps us understand God's love for us via Christ suffering it for us. But if that hell is only the psuedo -psychological version that Keller has swallowed from Kierkegaard and Lewis, then I haven't learned much of the depth of the love of God. We certainly don't get that picture from Scripture unless one does some serious isogesis, as Keller did with the text he used.
One's time would be much better spent studying Edwards to get an inkling of the astounding nature of hell, complete with God's eternal fierce burning wrath against sin. And consequently, we can then stand in amazement at the immensity of God's love toward us in bring the full weight of that wrath when crushing his Son in our place.
With all due respect, my friend, I think you completely missed the point of the sermon. Several points:
1. Keller does believe that hell is the punishment of God against sinners, which are the deserving objects of His wrath. His point is that rather than casting them into a literal "lake of fire," He allows their own sin to destroy them from within without hope of salvation. This isn't isogesis, but is confirmed elsewhere in Scripture. Keller didn't use this verse at all, but listening to the sermon I thought of Romans 1:28: "Furthermore, since they did not think it worthwhile to retain the knowledge of God, He gave them over to a depraved mind, to do what ought not to be done." We see again and again in Scripture that God's greatest punishments are giving sinners what they truly desire. We saw it with Pharaoh before the Exodus (God "hardened his heart" repeatedly), and with the Israelites wanting a human king (which led to their eventual downfall and division), among other examples. So I don't think Keller is reading anything into the verse by saying that God punishes sinners by giving them over to their unbridled depravity for all eternity.
2. I don't know if Keller believes in a physical location for hell or not - he didn't say in the sermon. Regardless, he believes that the torments of being devoured by sin for all eternity is far worse than literal hell fire, as he makes very clear in the first 3 minutes of his message. And Keller's favorite theologian is Jonathan Edwards, so I'm sure he's quite familiar with his teachings on hell.
3. For those of you who consider this view unorthodox, keep in mind the Westminster Confession's only mentions of hell: "And the souls of the wicked are cast into hell, where they remain in torments and utter darkness, reserved to the judgment of the great day." XXXII.1, and "...but the wicked, who know not God, and obey not the Gospel of Jesus Christ, shall be cast into eternal torments, and be punished with everlasting destruction from the presence of the Lord, and from the glory of His power." XXXIII.1. Not only is there no mention of "fire and brimstone," but Keller's view is 100% in agreement with the Confession.
I'm biased of course, since Keller is my pastor. And obviously I'm not saying it's wrong to disagree with him about this or anything else. But to say he's using "pseudo-psychology" and "isogesis" is far from accurate. There is nothing in that sermon that is theologically inaccurate or unconfessional. Keller may be completely wrong and hell may be a literal lake of fire, but if he is incorrect it isn't for lack of thorough and diligent study of the Word...