Hm, I hate to be on the bandwagon, but why WordPress? One of the things that has made PHP become what it is today is a focus on good software engineering and the introduction of language features that are required by that. WordPress did not keep up on the engineering front and there are so many amazing options out there now for well written, well engineered platforms. Even in pre-built blog platforms.

You're not alone mind you, most of the new platforms are not very popular just because of how embedded WordPress is in its ecosystem. It just surprises me that both WordPress never moved on and that the PHP developer community never chose something different when it was clear WordPress had no intention of moving to more modern practices.