Wishlist

Fine-tuned sliders

The ability to hold down a key, like shift or alt, while using a slider to make it be much more precise. Right now it is hard to use the slider to fine-tune things sometimes.

-- Old

Draggable resize the text editor

Have something like an anchor in the top left corner of the text editor and make it draggable to resize the editor

External, permanently exposed sliders

Would be great to have the ability so specify some variables to be always visible, even when the code is hidden, so that you could share a tributary with only the relevant parameters editable/visible. The UI for this would need to be though through. Maybe you only get 2 permanent sliders, and they have to be the x and y variable, for example.

-- One way to do this would be to define a protocol in the code so that we can easily search for it with a regex. I imagine something like this:
var x = 10; //min: -100; max: 100
we could match on just the format /var\ [variable_regex] = [number_regex]
and optionally support the min/max using the comments. We could then generate a slider for every variable matched in this way.

valid js variable name regex:
http://stackoverflow.com/questions/1661197/valid-characters-for-javascript-variable-names

gui generation:
http://code.google.com/p/dat-gui/
http://workshop.chromeexperiments.com/examples/gui/#1--Basic-Usage

#Infrastructure

Switching code editors

I've heard good things about Code Mirror
http://codemirror.net/