XFCE4 is my favorite desktop environment. I find it the most stable and useful amongst all other desktop environments available for Linux. It is solid, fast and most importantly, it follows the traditional desktop UI paradigm with a taskbar (panel), system tray, desktop icons and a launcher/menu. There are a number of improvements that were announced by developers for the upcoming XFCE4 4.14.
For the xfce4-panel 4.13, which represents an experimental branch for the upcoming XFCE4 4.14 release, GObject Introspection support was introduced. This should enable developers to write Panel plugins in different languages (e.g. Python).
Apart from this, a lot of fixes were applied to the panel's core plugins, including actions, clock, launcher, tasklist and systray.
I've spotted an interesting change in the change log. It has the ability to disable brackets for minimized app labels in the panel.
When you minimize an app to the panel in the current release, its label appears as "[app name]" in the task list. To get rid of these label decorations, you could apply a patch. For code samples, refer to my GitHub page, where I store the patch I use in Arch Linux:
Besides the mentioned changes, a number of improvements were made to xfce4-power-manager and xfce4-panel in the stable branch. You can read about them in the official announcement here. The author is an active contributor to XFCE4 and the Shimmer Project, known for its impressive GreyBird GTK theme.