There is no equation for what translates on stage. Some of the best performers are strange hybrids-Harvey, Carol, Gwen, Chita. Some can sing not dance. Some sing oddly and can dance. Some can style a song in their own unique way and can't dance. It's all about selling it. One of the most most effective versions of Bewitched was Stockard Channing's-she could barely sing it, but damn she nailed the pathos and the heartache and longing. She acted the hell out of it. If you can act like you believe what you are singing that's sometimes half the battle. Case in point, Glenn Close.
"The sexual energy between the mother and son really concerns me!"-random woman behind me at Next to Normal
"I want to meet him after and bang him!"-random woman who exposed her breasts at Rock of Ages, referring to James Carpinello