The skill set definitely has to be there ... with that said - some of the most skillful motorcycle racers in the world won't touch that course, and for good reason. So ... balls are apparently the game-changer for the folks who choose to ride the TT. It probably sounds pretty clearcut the way I explain it, and in reality - it's anything but clearcut. Just take a listen to any TT riders when asked why they decide to ride the TT... then listen to MotoGP & WorldSBK riders who explain why they don't, and you'll hear a particularly subtle difference.
Closer to the Edge was a great glimpse at the sport, and some of the most talented TT riders to grace the roads on the IOM today.
I'd love to visit the IOM TT one day!
jb_xx