Basically, Ogre is focused on graphics, so it requires other libraries to do things like user input. I wrapped OIS for that, but for making better GUI apps it's cool to be able to integrate with Gtk or wxWidgets. I want to look at SDL also. Further down the line, maybe OgreODE as a physics engine.
UPDATE: I meant to add that the wxPerl support isn't quite working, or at least the example isn't. Also, I'm not sure if
gtk_widget_get_parent_window(widget) is correct to call; I just copied it from what I found online, but it seems to get the wrong "parent" window. I need to work on the examples more. I'd like to get something like the GtkOgre widget working for gtk (it's pretty complicated to work out how to convert from C to Perl, though...). The wx example is (intended to be) a direct port of this WxOgre tutorial, but isn't working right yet.