I don't know about anyone else but when I get a new program and it turns out to be using a "modern" looking API I just assume it's going to be awful. Not just the UI but everything about it. I've rarely been wrong.
Note to UI designers: nostalgia doesn't necessarily mean "good". I can be nostalgic for my grandmother's cabbage soup, doesn't mean I want a daily banquet of the stuff.
You think Microsoft would have learned that "modern" has the stench of death.