I would say it's about half-and-half...with any Vanessa album there's a mix of darker and lighter songs.
the songs that I would call negatively emotive or "dark" at all might be Fair Weather Friends, Tall Tales For Spring and London (thanks to the newer lyrics).
other than that the other songs are more positive and have a positive outlook about them.... Carousel, Get Good, I Don't Want To Be A Bride
...and of course I can't say much about the other new songs we haven't heard yet.
Vanessa will forever have a dark side to her, that's just how she is. but I wouldn't call her completely "dark", she has changed and matured, her songs are more mature, but they still have light or dark elements to them.