PHP is an incredibly complex project which is being actively developed [1] and improved. If there were very simple ways to update PHP that were universally agreed upon, they probably would be added (Like short array syntax, built-in HTTP server or many other new features added in PHP 5.4). It just isn't a syntax issue, there are underlying principles about the way features are considered in PHP that are just different from other "similar" scripting languages like Python or Ruby.

If somebody had profound disagreements with the way PHP was being developed, they would be much better off switching or contributing to another language then they would be trying to re-invent PHP.

[1]: https://github.com/php/php-src/graphs/code-frequency