Magma Dragoon's Submissions MK-II

[puggsoy]

According to Wikipedia, the series was released as Dragon Warrior in North America until 2005, and none of the DS versions were released before then so you're right. However, I think they might be named this way seeing as they're remakes of the original versions, which were name Dragon Warrior in NA.
Technically they should be changed to simply Dragon Quest in terms of correctness, but on the other hand people might be looking for the remakes of what they know as Dragon Warrior.

I'm not sure, I'd want input from other people before I go changing any names around.