It boils down to figuring out a way to remove all the stuff that’s not needed in WordPress and coming up with a lean, modular core.

Rather than talking about vague abstractions like modules, forks, core plugins or a lean, modular core, it would be more productive to talk about specifics. What exactly can or should be removed from WordPress core and packaged into an optional module?

People seem to be talking about WordPress lately as if it's some kind of bloatware. It's a mature application supports a wide variety of server configurations. This is the reason that there are portions of the code that are more complex or more bloated than they would otherwise be.

WordPress does a lot, but I honestly can't think of a lot that would make sense to move into an optional module without causing unnecessary confusion or frustration for end users. Certainly none that would impact performance to such a degree that it's justified.

It would be good to get some suggestions from people for what specifically could be removed or placed into optional modules, and then discuss the impact and the advantages of doing so.