security causes a lot of limits for users and developers - Security will probably always be an issue, even with native apps. Anything specific you think could be changed to make web apps safer?

unhealthy competition between browser vendors, example: WebGL@InternetExplorer - Agreed. Especially when one browser stays from what's supposed to be "standard", yet rarely is.

its limited to 3 languages: HTML, CSS, JS (and its derivatives) - Agreed. Google's working on a compiled web language, but it will only work in chrome. They're attempting to make it a standard, but I'm not sure if any other browsers would put the effort into supporting it. And a whole new system like this would take years to implement. But still possible....