Yes. The knife tangent control. Limiting the speed of the motor will not collaborate all time with expected feedrate. Now, using tangent control, I should all time up Z before new line. (Tangent control doesn't work in circles, but this is not necessary at all). Preferred way is to treat tangent control as G1 code before next X,Y,Z movement. Difference is that my "knife" can cut when rotating. Z+, rotate, Z-, cut will give worst results. Doesn't matter how precisely done compensations in G code.
Exactly, this will be useful feature. Will hope to see it in some of next versions. Or it is present yet, but I don't know how to use it?