My understanding of 4e dragons was that individuals varied, but Chromatics were still evil and metallics generally were not, though they shifted to more unaligned instead of baseline good.
Here is the text in the 4e MMI:
Dragons are diverse creatures, appearing in at least twenty-five varieties within five major families. All dragons share certain characteristics—notably the legged and winged shape of their reptilian bodies—but within each family there are even stronger similarities.
Chromatic dragons are the dragons detailed here. They are generally evil, greedy, and predatory, and they’re inclined to worship Tiamat, whom they regard as their progenitor and patron. This family includes red, blue, green, black, and white dragons. Each variety has its own breath weapon—a blast of elemental substance, from blazing fire to frigid cold—which it can expel from its mouth.
Catastrophic dragons are mighty embodiments of primordial forces. They are destructive, but not devoted to evil. The ground warps and explodes violently in their presence.Earthquake and typhoon dragons are two types of catastrophic dragons.
Metallic dragons are in some ways the opposite of the chromatic dragons. Many of them are devoted to Bahamut and share his ideals of nobility and virtue. Many others fail to live up to those lofty ideals and succumb to a selfishness and aggression that seems common among all of dragonkind. Metallic dragons, including gold, silver, copper, iron, and adamantine dragons, often guard valuable treasures or powerful magic items, even artifacts. They have breath weapons similar to those of chromatic dragons, but their effects are as much defensive as offensive.
Planar dragons are dragons infused with the nature of other planes of existence. Shadow dragons, Abyssal dragons, and fey dragons are all planar dragons.
Scourge dragons, sometimes called linnorms, embody the afflictions that plague living creatures, much as catastrophic dragons embody natural disasters. They are almost universally evil, even more so than the chromatics, and they revel in the raw physicality of melee combat. Because they lack wings and rear legs, some scholars insist that they’re not true dragons, but more closely related to drakes.
