This article is good but misses a minor point: Wordpress was never intended to be MVC, the developers had probably never even heard of MVC when it was first developed. Wordpress is a bastard.
I've thought about how terrible actually hacking on Wordpress actually is, and truth be told, the horribleness is so entrenched that any kind of form or community effort to improve it would introduce incompatibilities with the ecology that are insurmountable. Wordpress is stuck.
> Wordpress was never intended to be MVC, the developers had probably never even heard of MVC
Not only the developers, maybe even most developers outside of certain communities. I'd been exposed to the concepts, but I'd never worked on an "MVC" site until about 3-4 months after the first release of WordPress, and I'd been doing for over five years at that point.
> I've thought about how terrible actually hacking on Wordpress actually is
Hacking core is pretty bad. Heck, even reading core to try and understand what's going on under the hood can be a challenge.
But writing themes and plugins is not that bad -- indeed, if it was, I suspect you would find a far smaller mass of them. It's not MVC, and particularly if you're used to that organization of a web app, it's disorienting, but the APIs are reasonably organized, well-specified, and let even n00bs get things done.
I've thought about how terrible actually hacking on Wordpress actually is, and truth be told, the horribleness is so entrenched that any kind of form or community effort to improve it would introduce incompatibilities with the ecology that are insurmountable. Wordpress is stuck.