Her history also makes her very interesting. I like characters who have unique, complex backgrounds (such as Kaldea). Even though Dominique is saved at the game's end, there is still something tragic about her; both her innocence and the fact that she has no idea of her true identity. Volt points that out in his ending. It's interesting to speculate how she'd handle finding out that she's a bionoid, even though the very end hints that she's found some sort of peace with it. In the end, it might be hard to destroy Dominique's good nature.
On more superficial grounds, I think her name is really awesome. Also, one of her coolest scenes is where she goes berserk on the Rocket Tower deck and kicks major arse.