The Blend Image with Feedback Node is missing a few parameters, I'm proposing a second node!!!
An absolutely essential parameter for feedback in my opinion is hue shift.
Also a "framerate" is very useful. So that not every frame is filled up with feedback, which allows you to create graphs etc.
There are also a bunch of parameters on "Blend Image with Feedback" that aren't very useful and can comfortably be scrapped to save space. Transforming the foreground image is redundant, and can easily be done with another node, similarly: width, height, colour depth etc.
An improved feedback would be soooo useful in my opinion.