Oh geez. This was exactly what I wanted -- the rivalry in genius, manipulation on Gellert's part smoothly transitioning into canon. And really? After JKR's revelation that Dumbledore is gay, this feels like a missing scene from the flashbacks to Dumbledore's early life. I would love to see what's going on in Albus's head throughout this.
Thank you, thank you, thank you! This is the best Smutmas gift I could have hoped for.