She crossed over though so that makes it a bit hard to consider what makes for real success. (As an aside, do you think Kat could handle any of her stuff?)
I would think that 100K plus sales would make for a decent jazz album. They don't get the hype that pop/rock/country do.
I think if Katharine learned to sing with restraint and within her natural range instead of making almost every song a power ballad, she might be able to do some Norah Jones.
Katharine seems to think she's a Celine Dion/Whitney Houston type of singer, but she simply does not have that kind of range or power.