Creep Issues

Im designing creatures for a little defense map i have.

Heres how it works..

- There are only a set number of creature types that can spawn.
Im currently using 6.

- Each wave consists of those 6 creep types in different amounts.
Ie. (Wave 1 has 5x Creep A) while (Wave 2 has 2x Creep A and 2x Creep B.)

- The creatures each have their own weaknesses and strengths and no two creeps do the same thing.

Basically I need suggestions on what types of creeps I should have.
Ive done some already.

Creep 1 - Heavy Melee Tanker.
Has slow movespeed and attackspeed but absorbs damage vewry well.
Creep 2 - Light Ranger
Painful agaisnt units but weak versus structures.
Creep 3 - Healer
Weak at combat but has powerful heal spells.
Creep 4 - Siege Ranged
Short ranged unit good versus buildings only.
Creep 5 - Mage
Offensive caster

Creep species should all have a unique role that no other creatures already do. Neither should a creep be "better" than another.

Well here are some suggestions I thought up

• Mage - Shoots out fireballs on attack. When out of mana, just starts shooting normally. Fireballs do HIGH damage but he has low overall everything (life, armor, movespeed).
• Destroyer - Somewhat like the Heavy Melee tanker, he has slow movespeed and attackspeed, med damage, but super high life and when destroyed deals damage in an AOE.
• Soldier - You could say this guy is the "average" creep. Average everything..I don't know?
• Assassin - Fast movespeed and attack speed, low life and med damage. There should be like a unique targetting system or AI to target Archers/Healers/Mages first, and then attack the rest.

Not much atm, but hopes this helps to get you started soon!

Yeah I think its definite that I need to have an offense "Mage" Creature.

Adds mage to list...