Oh, come on. WordPress could have started providing a decent API eons ago. They don't care. Or they fundamentally don't see there's anything wrong with spaghetti code and inconsistent API's.

The only reason they are abandoning PHP4 because it has become so rare they can't test against it anymore, not because they want to improve anything. Remember this crap: http://ma.tt/2007/07/on-php/ ?

Which is typical for WordPress: one of the most successful companies to be built on PHP, and all they do is bitch about it and use their influence on a part of the community to hold it back instead of contributing, like Facebook, Digg and such.