I'm basing my opinion on footage of LJ from Such is Life, where he absolutely slays, Head for the Hills, and traveling circus/clown school edits from this year where he's throwing doubles, spinning both ways, and grabbing the shit out of everything. I can't say that I've seen LJ hit an 80' ft. jump (though he almost assuredly has), but I think it's fair to say that he's more than capable.
John is sick of course, but he hasn't really been skiing competitively a whole lot since his injury last year and has been focusing on commentating and his expn blog. Other than the edit he made early this fall (which was cool and all, but clearly didn't showcase any "JOSS worthy" tricks), the last footy of his I can recall was from Yeah Dude. His seg was fun to watch, but clearly his strength is not in throwing stylish and technical tricks over manicured jumps. His pipe skiing, spontaneous backflipping, and particularly the shot of him skiing that vertical ice wall, really struck me...his jumping not so much - which is what this contest is all about.
I didn't intend to take anything away from Symms, but I think it's pretty clear that LJ, Martini, Ahmet, Hornbeck, Liam, Brown, Delorme, and probably a handful of others, would be better suited to a contest that is essentially just lapping a massive jump. I bet Symms would agree.
All that being said, John and Colby are hysterical and will probably put together a fun segment.