Court Ewing has a (slightly inflammatory) post to his blog that shares some of his opinions on why he thinks PHP is broken and a few thoughts on how it could be fixed. He's edited the article since its first publishing to include some clarification of his original ideas.
Before getting into the original post, I wanted to a comment made in his edit with an apology for the original post coming across as more of an "irritated user" than an unopinionated observer.
PHP's development process has been broken for a long time, and the failures of that process have swelled since the first ripples began to appear many years ago. [...] This is no surprise given the very fluid history of PHP though, and the lack of any sustainable processes may have even been one of the key things that allowed PHP to evolve so quickly into one of the most used programming languages in the world. But that early success doesn't make the PHP development process any less broken.
He covers a few points where he has issues with the PHP project including the release management, test coverage and recent issues with bugs in releases. He gives suggestions on how things could be made better - a detailed release process, a voting process for new features and a emphasis on good code and tests in the core. He also notes that he thinks more contributors in the mix isn't the solution. While it's encouraged to join the project, he suggests that the current core development group are the ones that should work the hardest on making things better.
Be sure to check out the comments for some great responses from the PHP community - both for and against the statements from the original post.