According to the Monster Burner, it takes a speed of 7 to “perform physical feats that leave others with their jaws hanging open” while Speed 9 is compared to Jackie Chan’s “Drunken Master 2”.
As humans are capped at Speed 8 there should be a skill that allows for greater training than what the average person can do on their own without training, and such a skill should be rooted in Speed (as are Dance and Stealth).
Considering that all BWG characters already have obstacles set for physical, acrobatic like actions, I propose that the current system is treated as “Beginners Luck” for Acrobatics, while those who have aquired the Acrobatics skill test their skill exponent at half the current obstacles.