So I have already suggested turn rate by moment of inertia. Alas I after doing some sums I found that the values to each end of the spectrum were far to extreme.
This is due to massive variation in weapon reach 40 to 300
So I did some more thinking and thought what if we had more variables. wpf and str were my subjects.
So now
turn_difficulty = (some_factor1)*(mass-(some_factor2*str))*(length-(wpf*some_factor3))^2
------------------> some_factor3 should not have the same constant for each weapon type
------------------> some_factor1 is from moment of inertia and should vary upon weapon weight distribution
------------------> any neccesary factors for the below equation can be included within some_factor1
turn_rate = (vanilla_turn_rate)/(turn_difficulty)
So being stronger and more proficient is better. However for longer weapons proficiency is more important than strength.