That's funny, I could say the same for you.
It's true that I haven't tried one-race armies per se, that is, I've never added that one last troop though I've had 4 troops of the same race on many occasions, getting a +1 to morale is a decent thing but I'd much rather make use of the special abilities of others like emerald green dragons for mana generation and general tanking, inquisitors for resurrection and their free bless, shamans for the totems and axes, demonesses for charm and teleport, necromancers for lvl5 magic lock and raising undead, ogres for dishing out huge ammounts of damage, and so on.