I recently decided to try help a friend put together an animated website which led to me looking into SVG and HTML5 animation tools wrt Linux.
It would seem to me that Sencha Animator, which is a pricey commercial app but at least has a native Linux version, is pretty much the only option we have currently if you don't have the patience, skill and time to hand code SVG and JS animations. There is sif2svg to convert synfig files into simple svg anims but synfig has no native svg export support and Inkscape, Pencil and Sodipodi say they plan to eventually support SVG animation but I don't think either has any real animation support yet. I found a JAVA SVG editor called sketsa which has a animation plugin but that doesn't work under the latest release.
Anyone know of any other apps, hopefully FOSS, that may (one day) be a viable alternative to Sencha Animator and Adobe Edge?