This Fedora 18 feature shouldn't come as a surprise, but Xfce 4.10 will be packaged up in the F18 repository (the feature spec). This isn't about Xfce 4.10 replacing the GNOME3 desktop by default within Fedora, but just about moving from Xfce 4.8 to Xfce 4.10 for what's available as an alternative Linux desktop option. Xfce 4.10 offers up many new features and much more after seeing a long development period.
One of the more interesting Fedora 18 features that was accepted today was the user mode migration support. From the Fedora Wiki feature specification, "Access control of privileged operations for ordinary users should be handled exclusively by a centrally managed authority. Usermode/consolehelper should be phased out and be replaced entirely by PolicyKit." This centralizing on PolicyKit is expected to ensure consistency of system configuration, centralization of policy, cleaner system integration, and no difference regarding the hook-up between tools installed in different locations.
Also approved today for the Beefy Miracle successor is the KRB5 DIR credential caches.
These new features approved at today's FESCo IRC meeting come on top already many other approved Fedora 18 features such as RPM 4.10, tmpfs, NetworkManager hot-spots support, and reworking package groups. Still being decided for Fedora 18 will be a long-standing feature item: Btrfs by default.