Agreed. The sanity started coming around circa 5.4 and has been increasing rapidly. The variadic operators will cut down on the number of lame func_get_args() hacks I have to write in my RESTful routing code :)
I'm not sure how long you've been around, but if you remember the way that OOP was implemented in version 3, you'll realize they've been coming around for a while now.
I've been writing PHP since right before 4.3 was released, but I was still a n00b then (I was in the 6th Grade) and don't remember a lot of the pre-5.2 quagmires.
The biggest was probably that pass-by-value and pass-by-reference was flipped on its head in PHP4. Interesting times in PHP land back then!