That's the first time I think I've heard that. I've heard many times that PHP is much better than it used to be, but in what ways is it more powerful than Ruby?

One nice feature is that it is optionally typed (php 5.6 had this for classes and arrays php 7 added support for specifying primitive types.)

Also, the newer parts of the language such as the object system and the presence of closures and first class functions are almost pleasant to work with: for the most part, the annoyances come from the old stuff

Not at all.

I abused Ruby's metaprogramming capabilities to build a small functional language with operators. I monkey patched symbols with operator overloading to add the typical functional operators such as composition (using * since . isn't possible). I created operators for piping, partial application, etc. Terrible abuses that probably reduced inter-library and future compatibility to 0.

I don't think that would be possible in any way with PHP without PECL (there is an extension for operator overloading magic methods) whereas it is with Ruby out the box.

If the language allows me to abuse it in such a way more than another, I reckon it holds more expressive power. Case in point: Lisp.

I'm really curious about this! I don't know much about recent versions of PHP - what do you think makes it more powerful than Ruby?