Hi Robin,
Just found your thought-provoking thread. A few thoughts...
I sometimes use a scroll mouse (at work) but more often do everything from my laptop trackpad. When I first starting using NodeBox I found the window interactions frustrating, but grew to appreciate them after discovering some of their poorly-documented features.
(e.g. hold space bar to pan, two fingers on pad to zoom, set output frame in document properties, check "Bounds" box to see output frame, etc.) Note to Frederick: I do wish I had the option to use a different control key than space bar (control, option, command, shift); this would allow me to pan when sharing my laptop screen to an iPad using AstroPad or Duet.
NodeBox has one of the nicest, simplest, most powerful ZUIs (zoomable user interfaces) I've seen. There are seven orders of magnitude of zoom which you can use to produce deep PDFs, interesting animations, etc. The zooming on both sides of the display is fluid and addicting.
As for tweening, you might want to search through some of the forum threads for discussions on morphing. As Frederick explained, NodeBox does not yet have a morphing/tweening node, but you can roll your own without too much trouble.
I have also experienced some choppiness in animations when there's a lot of computation required for each frame, but this usually smooths out when you export your MP4.
NodeBox is not intended to be a robust animation app, but it can produce some kinds of animations which are hard to do in other tools. And because it's vector-based, the resulting MP4 files are often dramatically smaller (in terms of file size) than typical MP4s.
It would actually be possible to build a crude video timeline UI entirely within NodeBox. You could render a timeline node to display multiple tracks and markers, reposition the markers by scrubbing X values on rectangles, then do lookups on their positions and use that to drive complex animations. Just change the rendering node to switch from timeline view to final display. (This is a pretty wacky idea, but I mention it only to illustrate that NodeBox is more powerful and versatile than it may seem at first.)
As for Export to GIF - yes, that would be nice! In the meantime, I think there are some tools out there that could do the conversion for you, either from the MP4 or from the set of individual frame PNGs.
I hope you will keep dabbling with NodeBox. I think its a great teaching tool (and lots of fun besides).
John