@Erlend Sogge Heggen [W]hat do you, wp devs and enthusiasts, think about moving WordPress on top of an established PHP framework?

Myself, I'm not entirely immune to the charms of frameworks. I've followed Julian Smart's wxWidgets, since way back in the wxWindows days.

Different framework-products come with different assumptions & decisions ... each set of which excludes other sets. When Microsoft writes frameworks, we know that the guiding principles prioritize behind their business-goals. When independent developers collaborate on a framework, it is mostly about making the world a safer place for their own chosen activities & lifestyle (rather than those of, say, the users). When educators become enamored with frameworks (yes they do), they tend to glorify pedantry.

Merely choosing which of the current PHP frameworks to migrate to, would be a major foment, at a large, well-established project like WordPress, using as it does many very loosely-associated developers.

If Matt Mullenweg was/is enthralled with frameworks, then he could help guide the community that way. Without strong interest & real leadership on his part, it seems like a classic armchair question.

I would not support a framework-movement, that looked like it would create instability & disarray for WordPress.