Welcome to the forums Kingtom.
We actually have 2 goblin units already, a goblin warrior and a goblin archer.
Orc's do have a spellcaster, though his name hasn't been confirmed yet, I believe he's either a Warlock or a Mor.
We are debating giving ogres the ability to throw rocks, they already help so much in siege with their giant clubs, they can smash through walls or doors quite effciently.
Good idea with suggesting units, you never know you guys might come up with something we will use, or perhaps it might be an easter-egg or an editor-only unit.