I'd say Gizmo's attachment is normal--you are his world.
My two are both wary of strangers (one of the only things they have in common) but they'll allow family members to briefly take charge of them on outings or something (e.g. if I have to go in a store and leave them in the car with their grandma or something). They are anxious but not over-the-top.
Our only real attachment problem is that there's apparently priority seating with me...Keegan will growl if Daniel (cat) or Piper (puppy) try to slip into a position either closer to my face or blocking Keegan's immediate access to me. Keegan and Daniel actually got into a wrestling match last weekend (picture standing bears) on my lap, which wasn't ideal. But I don't mind that they find me so appealing. lol
