Unfortunately, yes, the reason you're let down is that pumpkin ales don't really get their flavor from pumpkin: they get it from the spices. By cooking the cinnamon with the pumpkin and then boiling it for an hour, you greatly reduced its potency. Cinnamon flavor fades over time, which is why the recipe recommends the spice tea in the secondary.
Secondary: Thunderstruck Pumpkin Ale
Bottled: NB Bourbon Barrel Porter, Raspberry Wheat Ale-Fredo, FFF Zombie Dust Clone
Planning: Nutella Stout, Cider