I know what you mean. Personally, I think that he deserved a human counterpart. Dragons are just as intelligent as the rest of them, so, maybe it is because he is legally considered a pet, or slave. Sign the adoption papers, already! Or does she even know?
that’s just the universe pissing on spike
Neither are the diamond dogs, but they still became human in EG.
The reason Spike isn’t a human in EG is because he isn’t a pony in the normal dimension.
Edited