no, no, no, no, no, no....

Look at the heart to star morphing. How can you call it a "very cool effect"?! It's so damn ugly. It existed back in the day of Macromedia Flash 4 (maybe earlier), called shape tweening. Except there, you could use tween hints to control the transition.

Try this instead: look at the pairs of nearest points, take a heap sort of like 4 best matching pairs of points, and from those points traverse the curves, resampling the paths with less resolution. Now instead of interpolating positions, interpolate angles. This way the curves will naturally deform, instead of line segments passing through each-other.