i dont like the idea of a creature having 10 spells becuase thats too much.i will like all creatures to have something special and to be the more uniq posible.if you make every creature have 10 powers,no mather what ,it will be imposible to not have a lot of clones powers
i will like a dungeon keeper where every creature has different skills ,where the low class creatures as goblin ( yes i dont use trolls as example this time,its a miracle

) if they reach level 10 they can be still usefull because they gain some special skill (maeby a bonus at damage for every other goblin who is fighting at his side)
so i dont want too much powers for all creatures,i think most creatures should get attack ,plus 2 or 3 powers and maeby one special skill or racial skill(like trolls can desactivate traps ,or dark elf can go sniper mode,dragons go trought fire ,well that one is from lvl 1 but maeby they could get at level 10 resistan to fire attacks)
in conclusion:too much powers will inevitable create clones and some creatures will be superior to others in every aspect making the other creature useless,and i dont want that for dk,i will like every creature be useful so every keeper can make different armys and not allways use the same strategy