NCF – Extended list of Neutral creatures.

No, creature micro-casts play too important a role, as they greatly help the warrior and allow the mage not to waste a turn on an extra buff or debuff. Although this is just my IMHO.

I completely agree. But supporting and micro-casting can be done in entirely different ways. Daughters of the Earth for Orcs, for example, are able to cast spells during an attack. Djinns support even though they are fast flyers (though their primary role isn't support). So a creature doesn't necessarily have to be a caster-shooter with a book to fulfill this role.
Regarding creatures, [email protected] almost any creature can be given a couple of spells and, as a result, an additional support role. For example, giving some gladiators Punishing Strike — they incite themselves and allies into a rage. Earth Guards — Stone Skin. And so on... A separate unit for casting is not at all mandatory.