She doesn't hyperscale like syndra or viktor for many reasons, but she is a very solid pick into most comps simply because of her mobility. Her damage certainly isn't the greatest, but the fact that she can fit into most comps so well is due mostly in part of her mobility and kiting.
We can nitpick all day what champs are better at doing what. I can argue that Ahri's charm is a shorter cooldown, longer range blitz hook, but we all know blitz is still the king of picks. The fact is that she is very well rounded and highly mobile. A 53% winrate and 11% play rate indicate that she is indeed quite strong.
P.S. with 3 ult charges the base would be 1154 considering Spirit Fire refreshes and can relock upon targets. This also means the scaling would be (3.34x) as well.