Indeed HE battles are bit boring, because are the typical Total War army, and very similar to TWW1 armies.
Lizardmen are the most fun, especially when you get units that eat their opponents.
Mind though do not stack anything bigger than Skinks. While Saurus aren't monstrous/cavalry have twice the size of a normal human "unit". So if you pile them up only the front line it attacking. Use flanking.
Keep away any of your own units from the Kroxigors path, if you do not want them to flying over also taking damage. Kroxigors, are good to drop them inside 4-5 enemy units, and heal them with a Skink priest. When they are in the fray, then use a Skink melee unit to attack the flanks, but keep a mind when they are getting too close. Move the Skinks away.
Also, while HE are bit boring, they aren't that boring if you run 16 man stack, on Very Hard battles. (there is a Battle slider hidden when you set up the campaign inside the second menu).
I find it fun to play Legendary campaign difficulty, with VH Battles (max battle difficulty).