I think its really bad when you make a movie based off anime and the actors look nothing like the charactors they are supposed to be playing. I mean put a **** wig on them to try and resemble them at least a little. Don't cast a pale skinned person to look like a darker skinned person (and vice versa) .
Honestly, what the characters look like is less important than whether the story/plot and acting work well. There's a certain sense, especially when the source material is very single ethnic(ish), to broaden things a bit for a wider audience. Changing up the looks of characters can easily be forgiven by fans if the film itself is really good. When it sucks, those other changes just add to the glaring problems. IMO though, getting a character's personality and fit into the story right is vastly more important than getting the exact look right (especially something which in theory should be trivial like real world ethnicity when the story itself is set in a fantasy/alternate world). I'm far more concerned with writers/producers/directors who decide to "reinvent" a character or even whole world setting because they think their vision is so much better than the source material. They're almost always wrong. Actually, scratch that. I can't think of a single case where it hasn't been wrong.
But that doesn't seem to stop the next guy from doing the same thing. Yeah. Frustrating.