I'm honestly underwhelmed. Maybe it was just the clips chosen to show Quinn and Valor, but it seemed like in every kill, some other teammate was there and they were really doing most of the damage, or she was helped in escaping by those same teammates (or even enemies).
For instance, when Hecarim ganked, he charged her and knocked her back towards safety or she was dead. Her vault seems entirely too short range to make much of a difference. With the little pause in the end of the vault, it almost seems like you didn't need to bother pressing the button at all, since they'll simply catch you thanks to the little delay at the end. Perhaps it was just the clip chosen or something though.
Still, she doesn't have an escape mechanism beyond burning her ult. That vault is short range, even without the delay at the end, and the blind does nothing for somebody chasing you down really. It seems that to escape you've got to change to Birdo and hope that you can get away with your speed.
All in all, underwhelming champion spotlight. I sure hope that she plays out better than this spotlight, because if she doesn't, we've just received an AD that, while an interesting concept, is one that nobody is really going to use in any sort of serious game where they need AD power to actually carry the game late.