Vai does do a lot of "emoting" when he plays(unless you're referring to something else,I'm not a guitar player),but I listen with my eyes shut. If you had a stricter definition,please explain if you feel like it,I'm always interested in understanding guitar technique.
Vai has incredible feel, unbeatable technique. I'm simply not a fan of his tone......that's all. That's a matter of taste. I could play the rest of my natural life and not approach his skill level, but give me a Gary Moore or Frank Marino any day.