Vanessa definitely isn't playing what's popular right now, or every album she has would be a best seller. She hit the popular note on her first album, but since then has been going against the grain. So I don't see that as a valid argument.
I love Vanessa's music, and her strength in my opinion is her songwriting and piano.
If I had to critique her however, I'd say her voice however is probably the part I'd most want improved, as it just seems to be lacking just a little something in many of her songs, not certain what.
Or perhaps I'm just used to the over synthesized recordings of other artists today, who rerecord their own voices over themselves to give the vocals more power. Don't know. One can just feel a difference in power listening to Vanessa singing versus someone like Kelly Clarkson.
Not that I'm trying to slam Vanessa or anything, just noting my observations. Again, I love her music.