RHEL 7 will use xfs as its default filesystem type.
That probably seals the fate for the ext* family of filesystems for commercial installations. No doubt smaller distributions will stick to ext3 or ext4, but once Red Hat moves on, many others will follow. Mind you, it'll be interesting to see what strategy Oracle might adopt, in their quest of making btrfs the standard.
Either way, a b-tree based filesystem has now pushed out the outdated "pointer and list" technology.