Well, the wait is over.
HTML5 is creeping into the JavaScript API & esri are aggressively propagating new HTML5 components in the API. With the release of version 2.2 of the API we saw a set of experimental samples released using Canvas raster layers, file drag & drop, feature collections in local browser storage and tile caching in local storage in the browser.
With the release of version 2.3 of the JavaScript API we will see support for IE9 which will overcome the longstanding issue of vector graphics performance in all versions of IE. IE9 has implemented SVG as the new vector graphics language, bringing it in line with all other modern browsers. This represents a significant speed performance upgrade for graphic display between IE9 & earlier versions which used the long-neglected VML technology for displaying vector graphics.