Not going to act like he was the best, but early Kane was really good at emoting with a mask while having a non speaking gimmick.
Being able to ramp up the emotion in a promo without it sounding too Pro Wrestler Promo Voice-y is kind of a lost art these days. Mick Foley was the best at it I can remember seeing, and the only one who seems to do it on a consistent basis now is KO. Which considering the structure WWE has in place for promos is even more impressive.