This one may be somewhat relevant (it can be done even now perhaps) but how about implementing an animated Zoom Blur? Zooming in or out with a slight blur at the corners. Perhaps it can be done with clouds and then… crap, I forgot how I did it. But yeah, animated.
Also, it would be good to have a camera similar to ToonBoom or Retas!Pro
It’s just a suggestion anyway.
One developer has been working on implement opengl as renderer and also he planned to add a camera feature to synfig. Unfortunately he has other occupations now and the development has been stopped.
Regarding to the zoom blur you can do a fake thing:
You should know (or you have to know) that canvases in synfig can be exported. It allows to reuse them several times on the same animation with the paste canvas layer.
So if you have a copy of the current animation and blur it and mask it making a hole in the center, you can overlay the result over the original image doing the illusion of a zoom blur.
Anyway it is just a workaround.
Can you post an example animation of the zoom blur that I can look at?
Radial Gradient blur for the win!