That was certainly the idea behind it. I've been thinking of "Dragon Knight" as the profession that could fill the "evil knight" archetype, without simply copying what everybody else does with Death Knights or Dark Knights. In this case, they're also unique in that they're not necessarily evil, but they're simply using corrupting powers that are considered evil, or at least dangerous to use, for the sake of fighting back against those who actually are evil (or, as is the case of the Elder Dragons, at least considered a "bad thing"). Which plays extremely well into GW2's notion of you playing a flawless hero character.