You need to highlight his role on the back cover or something. "THE INIMITABLE JOHN TRUITT RETURNS!"
I never want to over-promise and under-deliver. John's great in Summon Night 6, but it's a much more mellow, unemotional role than Ghaleon, for example. His line delivery is sublime, but Ist is an emotionless overseer for most of the game, so you won't get many crazy "MAGIC EMPEROR GHALEON!" over-the-top moments.
The cast in this really came together, though. I was concerned because there were SO many parts (like 60) and we farmed about 20% of the (20,000) lines out to BangZoom! because it was too much in the time we had on the crazy schedule for this monster of a game. But we're playing through the game now to debug and it's really pretty seamless. Easily the most voice I've ever done in a game - like 18 hours total.