Races never go quite the way you'd expect. For a general start: how many people do you think play each class, in a no-projectile race?
Would you believe that witches outnumber rangers, and that both of them outnumber scions?
What it looks like, from my perspective, is that people get so used to Scion = ST that they forget to consider any other potential alternative. On the other hand, everyone knows witches and rangers have to kill Hillock with their bare hands, and a fair few of them have figured out that firestorm, firetrap and reave exist. Fire, by the way, is a fantastic way to handle no-projectile racing, for this exact reason. The metagamers who don't poke into the statistics are likelier to pick one of witch/ranger, while scion gets passed over because, well, scion's a good racer and she starts with a usable weapon, right?
Which means my 2h cleave/leapslam scion gets a free pass to the top. I am okay with this. It's not quite refined yet, but considering all I knew when I started the race was (1) scion gets cleave from Hillock (2) race stats show that the meta go-to class is scion (3) I've never played cleave in my life (4) I'm going to do it as melee on almost 300 ping...
...I'm going to say that worked out pretty well.