check out those threads:
http://forum.1cpublishing.eu/showthread.php?t=5727
http://forum.1cpublishing.eu/showthread.php?t=4979
http://forum.1cpublishing.eu/showthread.php?t=5467
And many many others... there are some about undead armies (specifically vampires) and some others, damn I can't even remember off the top of my head all the methods of completely dominating the game.
Dryads are just a cog in the "power puff" strategy... that is... get anga's ruby and dryads, lake sprites, demoness, and i forgot the other females... anyways the demoness can swap places of friend and enemy troops, the sprites have a no retalian attack with very VERY high damage and extremely fast movement (especially with the ruby giving +3 initiative +3 move +3 morale etc... and morale itself giving 30% boost to attack and defense)