Back to Kara's original post.
I really liked the idea of making a *2/4/6 pet cast buffs at someone.

Yes, I admit giving a spell like haste to an enchanter pet might be less than agreeable (its only disagreeable if you don't want enchanters to have haste).

But I love the idea of giving pets a functionality besides being some castle raiders target practice.

Familiars give mana, awesome.

Golems could give strength enhancements, example.

Cleric pets can give armour of faith, example.

Dracoliches can give lich form, example.

So many useful spells that arent overpowered like unto Bind demon lord could be given to pets.

Lesser pets could be given faerie fire even, making mobs easier to be hit.

The longer I write this the more I think pets with spells is a great idea!