Why would the Lt class be "out of control"? Car/driver weight has NOTHING to do with driver control. If it did then the Lt. AA would be flying off the track. The whole Lt. WF being dangerous is a Dave Preston/QMA thing. He is trying to protect his DECO boys business. That is the simple truth.
I don't know why a Lt WF would be out of control, but I will tell you that Car/driver weight has EVERYTHING to do with car control.
If you can put your weight where you want it (light driver) you have a huge advantage over a driver that is heavy. The heavy driver will have more weight transfer going through turns. The lighter driver can have weight placed in areas that will help it corner better.
I wish QMA had gone to a light and heavy WF class last season. My 120 pound 13 year old (much of that upper body weight) was racing against kids that weighed 30 to 40 pounds less then he did.
It's a little kids sport. It is the only sport I know of where the younger, less experienced participants go faster than the older, more experienced kids.