30mm/s^2? That's very low ... I've got mine at 2000mm/s^2 on X-axis and it can do more. The moment of inertia of all those pulleys, particularly the 72T ones, will be quite high. That will of course limit the acceleration, but it probably won't be as high as my rotating a ballnut and pulleys.

I'm beginning to think though that high deceleration is actually bad as it causes the Z axis etc to flex very slightly (due to it's kinetic energy...) and 'overshoot'. Would be nice if you could set different values for acceleration and deceleration.