I've always felt that Flash's influence on paving the way for the modern web gets overlooked. Against the backdrop of a web that was painfully fractured and def

I've always felt that Flash's influence on paving the way for the modern web gets overlooked. Against the backdrop of a web that was painfully fractured and deficient of features, Flash basically innovated the hell out of all the worst parts, and then slowly but surely browsers and web standards adopted the best innovations (and ignored a few missteps). People talk about Flash dying or being killed, but I think of it more as having served its purpose, in a good way - if the open standards are no longer deficient, then there's no need for proprietary solutions that work around them. So in that vein, I think the features you've listed are basically the last few good bits that haven't been adopted (or covered by frameworks) yet. But I suspect 1-3 are kind of the same problem - that HTML's never had a good container format.