It has surprising depth and subtlety amid all the laughs and thrills. The "Let it go" moment is great, because although Indy is estranged from his father, he has spent his life seeking validation, and proving his own worth as a son, by working in a similar field. As he reaches towards the Grail, desperately trying to grab it, it's symbolic of his desire to please his father and for validation in that respect. But when his father calls him "Indiana" it's a means of expressing that he already had his love, was already proud of him, and Indy had nothing to prove. The unconditional love of the father is the true Holy Grail.

I probably should have put that observation in the article, on balance.