PCMan, the founder of LXDE, told me a few ideas about "how to make lubuntu better":
One thing I think every developer can do to make Lubuntu better is quite simple. Lubuntu developers can help check if dialogs in LXDE programs can conform to Gnome HIG. Currently, most dialogs in PCManFM/libfm are designed with Gnome HIG in mind, but there are still some missing bits. Since glade is used to create those dialogs, it's not difficult to fix them. If a dialog is too big for devices with small screen like Netbooks, "this is a bug" and should be reported in the trackers. Help is also needed to make them fit small screens. Most of time I develop them with small screen in mind so this might not a problem, but we need to make sure. Another thing you can do with the source code is making sure every GtkDialog is created with gtk_dialog_set_alternative_button_order() called. This is required to make all apps work in consistent ways. To improve user experience, those are things need to be ensure.
* Lightweight X Desktop http://lxde.org
* PCManFM/libfm http://pcmanfm.sourceforge.net