Why death? Every color has dragons. It doesn't seem like Arsenic is a sufficient reason to select the color. Is it just because the upgraded dragons of that quanta cost 10 instead of 11+? Do you find "turn one five pillars, turn two dragon" to the big attraction?
With Life, you can get a dragon that can't be killed even after Oty goes 1/6 on a Phoenix, nor after Fire Storm has been cast.
With Water, you can get a dragon with a better cost:attack ratio, and have creature control sidecard choices.
With Gravity, you can get a a 'dragon' that costs 5 and isn't affected by shields, as well as more interesting side card choices (like otys of your own, or black holes).
I'm not saying you made the wrong choice, I'm just curious what comparable strategies you found death to be superior to?