@Mega BirbDiana is intentionally made to be a tiny midget, she's kinda like a halfling dragon, in spirit. Victoire on the other hand is kinda wrong, she should have ~154 cm, even so that's mostly because she doesn't age normally after she came to the Nexus, this she's stuck in a 14 years old body, or so.
As for boobs, I guess I'm a subscriber of the Boobs of Steel tropes along with other things that make a nice looking serious anime girl, especially if she's a character intended to be a Lady of War type. Also, who can day that they don't like boobs?
If I wasn't at work and using my phone, I would get the Oppai Dragon Song now, what a loss of a great chance, sigh...
Man, I like Ni-Mu's theme a lot, and then the vocals start. And it feels like the singer is bored and that makes me bored too.
Are you used to listening to IA, or any other Vocaloid, for that matter? I'll reckon that that song is a bit slow, but not so much. I don't feel anything particularly boring about it.
That said, I'm a serious fan of IA, so I may be liable of biased judgment when when criticizing her songs, as long as they aren't do awfully bad that it hurts my ears, of course.