It maximises the leverage/torque of the servo as you can put the pushrod outlet closer to the centre of the servo plus you get better servo resolution and any slop in the gear train will show up less.

I tried what you were going to try on a modified Alliance and couple of years ago. Basically huge output arms and 100% ATV. At full speed it was like you were just doing a normal roll and well you chopped the power it would immediately start rolling faster. That was with hi-torque servos and 6V. I then put on smaller arms, upt the ATV and lived with the slower surface movement and it was cured.

Angus