In reply to Miroslav Glavic.

What delayed it? A great community with responsible development leadership. ;)

No one wants to release half-done or buggy software, especially when it powers over 20% of the web, and there are still a few bugs that need to be ironed out: https://core.trac.wordpress.org/report/6

Remember, WordPress is open source, so don't be afraid to get involved with the next development cycle. There are plenty of ways to help: http://make.wordpress.org :)