To be fast the most important thing is to be stable in gusty conditions. Only a thin profile can cut through the gusts like a knife. When you watch racing today there is a permanent working on the bar: depower ... power ... depower ... power and so on. That´s wrong. In future racing you just pull the bar once for acceleration and then lock this position. No movement of the bar anymore. Similar to slalom windsurfing where there is no movement of the boom either.
So control and an absolutely stable unit of board, rider and kite is the key for speed. That´s way more important than theoretical performance (high aspect)
Maybe in the future kites eat gusts so well that you don´t need any depower anymore. So you can use kites with only two lines. That means less drag = more speed.
Clickbar without frontlines