Last week, I wrote about some of the new features we can look forward to in WordPress 3.6, still in Beta. Among them were custom post formats, which would give the WordPress dashboard a slick feel reminiscent of the Tumblr dashboard.
But a few days ago. WordPress dev Mark Jaquith announced that the Post Format UI is being killed in the upcoming WordPress release.
If it is implemented at all, it will likely be implemented as a plugin, which is where it belongs, in my opinion; NOT in the WP core. Leave the core clean, and save the extras for those who want and need them. This is the only way to avoid WordPress becoming more bloated than it already is.