I can see Shyvana being terrifying, but only in the right hands. Just had a match against one. She went like 30/5/10 or something ridiculous like that. Problem is, nobody on the rest of her team had more than five kills. She could single-handedly take any three of us at the same time, but we took to moving as a group and she was of course no match for us then. I was a jungle Nocturne built semi-tanky*; I would ult in, fear her, our Malzahar would ult her, and we would focus her for however long it took, after which point her team of malnutrition victims could do nothing to stop us from pushing. I think the match ended 55/40 or something ridiculous like that. I'm pretty sure the other guys could have won if she had shared the wealth a little.
*: I don't usually get Frozen Mallet and Atma's when I jungle, but my other mates were Malzahar, Karthus, Lux and a glass-cannon Pantheon so I kinda had to be the initiator all game long. Fortunately I must have done a decent job.