Browsers are too complicated and this is bad, for example, for creating more competition. And the reason they are complicated is there is too many web standards and too much legacy to support.
Want to make browsers easier ? - removing JavaSript and *fixing browser bugs instead* ('outsourced' to the user) will do that better.
BTW JavaSript it's not W3 standard, XSLT is.
("Live and let live", "Don't break the Web" - "breaking web pages that were made 20 years ago is unlikely to result in bug reports")