just from engineering point -
increasing the amount of material on the arms WILL make the car less responsive and will slow down the car.
Simple - you're increasing the unsprung weight - this is weight that is below the suspension. This is ALWAYS bad weight and all car makers try to get rid of unsprung weight.
the only way to "make the arms stronger" is to increase the amount of material on the arms. They're already triangulated and gussetted about as much as they can. The only thing that they really could do would be to make solid arms (like the OLD Yok ones) which would make them very heavy (those things were HEAVY).
A lot of it has to do with the angle of hit.
Plus the amount of cars on the track. If you go out on a small track with 12 other cars, you're asking for a break and it's not the car's fault.
I won't take my 10L2 out on the track with more than 7 or 8 other cars (for practice) even though I could easily take on the sedans with it and drive away.
I agree with Andy M