OK, I have this idea for button with a shortcut to create frame by frame animation easily.
Let's start with the AS normal behavior: when you draw a line, the line and points will be on the layer for ever, even when you turn off the visibility or select an absolute alpha color or whatever. You can hide the shape, but the points will be always there. You can't erase points in the middle of the animation without losing them at all. They are there or they absolutely aren't there.
This behavior makes that make a simple frame by frame be very tricky in AS.
My idea is to create a button script which take the created points and reduce them to a very little single space (I mean, all points on the same far x,y coordinate so they will look like just as one single point) and turn all shape alpha values to absolutely transparent.
That is how I imagine it working: let's suppose you have a ball which fall in water and you want to animate some simple lines for drops sprinkling from water.
For a sprinkling effect you just need, for example, three frames with three different drawings. Just like in next draw

To make it, create a new vector layer and in the frame the ball touch the water you rapidly freehand some drops. Then, in next frame, you press this script button. It will create a new keyframe taking all points and shapes and reducing this to become a little invisible point and also changing the new and previous keyframes interpolation to step. Then, you draw the second frame you want. Ok, now advance to third frame you want, press the button -same hiding process- and draw the third frame. Go to next frame and press the button again.
This way you will obtain three different draws on the same layer. No interpolation, just for make some details, as the drops falling or for drawing lines of velocity of an arm moving fast.
I think that the step interpolation could be automatically added to have the ability of make draws which be visible more than a single frame. So, you draw it, advanced two or more frames, press the button and draw another thing. As the interpolation is set as step, there wouldn't be a black hole animation, just a change of draw.
I'm sorry this request be so long written. I just want to be sure you capt the idea (and as I don't trust in my English, try to explain it very carefully).
What do you think?
Thanks!