If im correct
Steve Morse holds his pick the same way as you do: with his pointer, middle and thumb. And if its good enough for Steve...
I know that Gilbert completly changed the way he holded the pick after playing for seven years. He used to hold it like you do, but now he holds it with the side of his thumb and his pointer. Its possible to change the way you pick but it takes A LOT of work, especially if you used your technique for so long like you did.
But if you happy with your technique the way it is, why change it?
Good Luck!