Form, you'd name a dog "Maggot"? Poor thing.
EDIT: Cross-posted with Firefoot, who has similar reservations...
"Gandalf" is a good, sturdy, dignified name, one that a dog can grow into -- and it works either way: if your dog turns out to be a real dummy, then Gandalf plays ironically; if your dog is unnaturally wise (I know, a longshot, but I have known wise dogs in my time), then it's a perfect fit.
"Many are my names: Gandalf to my mommy, Big Dummy to my daddy, Hey You! to the neighbor; to the woods beyond the back yard I go not."