I think at this point WordPress is so ubiquitous that a fork isn't recommended and more importantly would probably not succeed.

Entirely new solutions like Ghost have a better chance of gaining some traction starting from scratch rather than forking WordPress. But it's still a tough row to hoe. This isn't exactly a space lacking solutions. There's tons of blogging apps and CMS apps out there. But Ghost is very promising and it's garnered a lot of attention which will give it a huge leg up when it comes to gaining some traction.

As for core plugins... I didn't expect them to gain traction. So it's progressed exactly how I thought it would. Good plugins are products themselves. To do them right if it's anything other than extremely basic functionality is going to take dedication and lot's of effort. Dedication that would be better focused on the core rather than a plugin given it's development not being done for money.

But I do agree that the best usage for Core Plugins would be to remove functionality from core itself and provide it as a plugin.