My only problem is with bards casting healing spells is that they are supposed to be an arcane caster. If the bard can cast healing spells then it makes sense that a wizard should be able to do the same thing since they are both arcane casters. The wizard is much more conversant with spells than a bard. I have gotten around this by saying that the "spells" a bard casts are not arcane, but a class unto themselves.