Yeah she's created some hits for people like Rihanna and Beyonce. She probably would've have sang "Diamonds" better than Rihanna.
I love Kyo but he's not necessarily underrated, well at least not in the rock/metal realm. I've seen quite a few American metal bands lauding his voice and versatility. I think Dir en grey as a whole are underrated, but then I listened two their last few albums and they're just not holding up.