Lorteungen
Warlord
Rugged defense was a great concept and it wasn't really all that random. A fortified unit would slowly gain entrenchment level, starting at 0 (moving units) and ending at 9 I think, with about one level added per turn. At higher levels a rugged defense was very likely, while at low levels it was very rare (I'm not sure it could happen at all at 0). An entrenched unit could be softened up by artillery or air bombardment, reducing the entrencment level. Also, engineer/pioneer troops were immune to rugged defense and were great at insta-clearing a heavily fortified position. It worked great in PG, but I'm not sure it could be implemented well for non-modern combat.