I think JavaScript is largely a pox on the web. I hate almost every website I come across today. I just try to ignore all of the bullshit for as long as it takes to consume the actual content, and 95% of the bullshit is possible thanks to JavaScript.
Do you think if JS weren't available advertisers and marketers wouldn't try everything to shake some $ off your pocket? You would be pissed the same way.
Also if it weren't JS, would it make a difference if the bullshit is created by lisp, java or erlang?
That's just laughable. Somebody at some point would have created an alternative browser with client side scripting. Otherwise you end up with static text and video. Wonderful. And plugins! Because you don't allow scripts :)
I don't think that it was a mistake at the time. I think that in retrospect it has been abused, and many of the things that justified it are now possible without it. It should be deprecated and removed.
Yes, I know this is a fool's errand. I don't actually expect this to happen.
A UI markup language could define forms that are "desktop-like" without involving a Turing complete language.
The paradigm of the HTML form with controls and a submit action has not been developed to its full potential, because it was basically derailed by JS.
It could have a lot more widgets, and there could be some standard way they exchange and validate data, without a full-blown client-side programming language.
For instance, say you want the user to pick a date. There could be a standard widget in HTML for doing that that could be dropped into a form, and it could be configured to communicate its value bi-directionally with some other field. (Perhaps like cells in a spreadsheet or that sort of reactive thing.) A rich set of standard widgets with flexible styling and layout, communicating the content of the data model to and from the server. Something like that.