Quote from IMorphling89 »With the Wildfire package, I would agree that Thundermaw should get the nod, but without it I think both Goldspan Dragon and Glorybringer are better cards.
Can't say I fully agree with Glorybringer / Goldspan Dragon being better cards than Thundermaw Hellkite even without the Wildfire package. Thundermaw Hellkite is still the deadliest / most destructive 5-cmc red dragon out there with the fastest clock. While Goldspan Dragon does have some nice synergies with artifacts and ramping in general, having the least destructive power of the three makes it the worst of the 3 in my book overall.
Thundermaw Hellkite zapping X/1s in the air is huge for closing out the game, making it very difficult to wall. Most things in the air are either a 1/1 or a 4/4, which makes it near contestable in the air since very few things can trade / beat it in combat. Even then, it's able to tap those creatures down when Thundermaw Hellkite ETBs anyways, which gives it a good shot at racing your opponent.