I was under the impression that the F117 was angular because the computers they used back in the 70s to compute the stealth shape only had enough power to work with flat plates. Advances in computer technology since then have allowed the stealth calculations to be applied to curves as seen in F22 (designed 1986ish).
If this is supposed to be a "modern" stealth helicopter then it should be curved. The angular design implies it was designed pre 1980 which seems unlikely.