If Marcus' timeline is correct (I've not been around PHP long enough to know) then PHP5 is already two generations of leavers behind, as it seems to be heading towards Java-style OOP. There does seem to be support for that static style of OOP in the PHP community though, as you can see in the "Design an ApplicationController implementation together" thread:
That seems to me like a step backwards, away from the dynamic nature of PHP. And I have to agree with Marcus' analysis, language level bugs worry me.
public function validate(DataObject $data, ILogger $logger)