Well, if I was to predict the future I would say that we will see new browser architectures that will allow new types of code to be written that are not currently possible. I think web browsers will be more like a VM that can run any kind of code compiled to them instead of being forced to render only HTML and JavaScript. I would take a look at the things about web development that people currently complain about and would venture to say that some smart people will get together and address them.
Perhaps, if it wasn't for the screwed up security model that prevented you from doing a lot of the exact same thing that the browser prevented you from doing (for "security" reasons), the fact that most java applets had a UI that looked like shit, and that you had to write it in Java. I'm thinking more like improvements uppon Adobe's AIR platform.
