You’ll need to invest in its defences to ward off invasion from the ruinous powers. Here is my take: HE: Eltharion (but Alith Anar, Alariel and Imrik are solid choices) DE: Rakarth WE: Sisters, by a longshot Skaven: Ikkit (the most fun of the whole game) Lizardman: Tehenhauin if you want a bit of challenge, Gor Rok if not. So i guess their fun because it challenges me to think up different ways to deal with my enemies and fight my battles. The Cathay faction is defended from the Chaos Wastes to the north by the Great Bastion like the Great Wall of China, but defending against something far more deadly than Mongul horse archers. Tyrion and Grimgor are the most boring LL for their respective factions, imo. I figured if i plugged up the bridge half of them would run away and escape briefly after battle was joined, so i allowed them off the bridge and built a little L shaped lane so that they all piled off of the bridged i also put my best troops on the edge so that they encircled the enemy and massacred them.
I eventually worked out ways of minimizing escaped enemies and my shining moment came in a bridge battle an army of 1500 or so dwarven warriors led by Gimli against 4700 something gobbos led by their chief. Sieges on the other hand were just fantastically brutal and fun. My field battles would always devolve into me chasing hundreds of snaga into a corner for a brief slaughter before the majority of them escaped.
So my Dwarven campaign began with copious amounts of frustration. In previous games i would always play cav heavy factions. The most fun faction for me would be the Dwarves.