I see some aspects of the Shack much the same way. Young didn’t intend to write a theological study of the persons of the trinity. He was describing via fantasy, a journey of the heart of a man back to the heart of the God who loves him.
Two very positive aspects of the Shack have stuck with me. First is the beautiful way Young paints the relationship among the Trinity. Our God — Father, Son, Holy Spirit, one true, eternal God, the same in substance, equal in power and glory; although distinguished by their personal properties — this Triunity since forever, have been in a heroic, intimate, loving fellowship. I love how Young brings this out. Jesus, equal in power and glory with Papa, is always deferring to and honoring Papa. And Sarayu, flitting across the pages, was always pointing to Jesus. Long before Creation, there was active love, in and among the persons of the Triune God. Just as Lewis captures the power and love of Jesus in Aslan, Young captures Trinitarian love and honor as has no other work of fiction I have read.
The other sticky point for me was being reminded that since before the foundations of the earth, before I had ever done anything, before creation and the fall, sin and redemption, God knew me and fore-loved me.
I hit The Shack at a time when I was dry and had been dry for a long time. Young offered me a cup of cold water in Jesus name. The cup had a chip or two, and Young’s hand shook a bit, maybe. But the water was the real thing, pointing me back to the God who loves me, who is especially fond of me.