Brutal honesty following.
The dinosaur was my first thought, then the Wizard of
Oz.
Dorothy sounds like an old lady name to me. A bit of teasing potential in my opinion. I prefer
Dorothea, it has more spunk and I can see it across all age groups. Less immediate teasing potential too.
Dorothy Grace is insipid.
I don't see the appeal of
Dot.
Dottie is like loony/crazy. Dorrie or
Thea (and even
Dora) would be more palatable.