> Only by dropping Phase we can truly use the benefits of smooth animations like controlling (dynamically) the speed of the animation

I am not sure I understand this part of your post. How is Delay=140,Length=-1 different from, say, Delay=1,Length=140 (with modifying Length in the script) to provide synchronized movement?

> > mixing two animations that use different bones: individually animating f.e. upper- and lower-body (or door and forge!)
> e.g. Aiming the bow while running

But this would still require a second "Running" animation in which the Clonk does not move his arms, right? I mean, he needs to hold the bow somehow. Hm... or the running animation just needs to be separate from the "move arms back and forth" animation...

I think this can even allow mixing multiple animations that affect the same bones, btw, using (weighted) interpolation.

What could the C4Script interface for this look like? Would the following functions be sufficient?

bool PlayAnimation(string animname, int length[, int weight?]);
bool SetAnimationPosition(string animname, int pos);
bool StopAnimation(string animname);

Length can be 0 to not play the animation automatically, in that case SetAnimationPosition needs to be called whenever the animation phase is to be changed. An animation that is already being played via the object's action cannot be started this way; if the object's action changes to an animation which is currently played via this script interface, then an implicit call to StopAnimation() is performed and the action playback takes over.