The next Seth Morrison will have to be a skier who puts WAY more emphasis on big-mountain shredding and hucking than park skiing. That may sound obvious, but in today's game it's not so easy with all the hype and fun of park, rails and backcountry booters.
As it exists, I don't think any current pro or semi-pro has what it takes to be the next Seth. Jamie Pierre has the stunts, but that's it. Somebody like Dana Flahr is a pretty good rider, but he won't be able to develop the attitude and image that Seth had. The closest thing may be somebody like Julian Carr, but I don't know that he has the ability to ski the big, steep stuff like Seth did. Seth's turns were just beautiful.
I envision that some new kid would have to come up through a cross between the big-mountain comp circuit and backcountry scene; somebody who had a focus on that stuff primarily. Then he would have to be lucky enough to have a major film company like MSP or TGR nurture him while he gets his feet wet up in AK and BC, which is just really, really rare.
I foresee the next Seth having to come up out of Whister, Jackson Hole, Alta/Snowbird, Crested Butte, Tahoe, Mammoth or maybe Mount Baker. And any East Coast kid wanting to be the next Seth just better get out west as quickly as possible.
Just like there won't be another Michael Jordan, Tiger Woods,  Tanner Hall, Candide Thovex or Shaquille O'Neil for a long, long time to come; there won't be another Seth Morrison for a long-ass time either.