How Good Would Hellmuth/Matusow/Etc Be If They Weren't Tilt Monkeys?

[PokrLikeItsProse]

If players like Matusow or Hellmuth or anyone else known for blowing up at the table had reasonable level of self-control (let's say the level of Daniel Negreanu, who has been seen to tilt on TV, and not some robotic untiltable demeanor), how good would those players be?