Let me put it this way.
You see Saber Offense and Defense Lv. 3?
Staff and Dual get a faux 'LEVEL 4' over single from their hardcoded bonuses. This is not subject to argument: they are not balanced, single users just have this nasty tendency to be more highly skilled to make up for the power deficit. Either that or they use exploits. Axe the exploits and you're still stuck with staff and dual's hardcoded advantages.
What's GBF? Go Back Frontal?
And honestly... That's some weird empirical evidence. I see staves as first place in frequency, with dual and single BARELY tying for second...