No. But she deserves to be.
She has one of my favorite voices of all time. Because, yes, while a lot of amazing singers are great, some of them get tiring or indulgent after a while. Kelly's is just that type of voice that I can listen to all day without wanting it to stop. Even her high notes just sound lovely in my ear. Very few artists have such a beautiful resonance like hers.
That's just my opinion.
I think the reason she's so underrated is because her songwriters could be better. Especially as of late. Breakaway was incredible and My December had some of the most amazing songs she's ever recorded (Never Again and Sober are probably my two favorite songs of hers). But I wasn't too impressed with the last two records. She's so much better than that.