It really is unfair. I mean, even though I didn't like that they made Spike into a dog in the first movie, after a while I kinda understood how it could've been more convenient for them, what with the whole talking-dog helping prove Twilight was from another world, or how it would be weird to have a little boy following her around everywhere (and if we count Rainbow Rocks, it would've been even weirder for him to stay on their sleepover O_o), so I eventually let it pass...
But this. Oh god, this...this was a slap in the face. How come even those THINGS get to be human when poor Spike is still stuck as a dog? Even though I know there's almost 0 chances, really I hope something happens that allows Spike to become human in any future EQG movie. Who knows, maybe if he does grow a little in the show (like teen dragon) the next time he crosses the portal he'll get turned into a human too. Wouldn't make much sense if they don't come up with an explanation though, and I don't see them taking the effort to do that for poor Spike
Yes I know about human-world Spike being a dog, but maybe (we can always dream) something will happen that will make EQ Spike become a human in the human world. Maybe the result of a spell or something. There's not many chances, but you never know.
Basically every sentient being becomes a Human,.....except Spike, because in the show hes treated like a pet, a dog. Plus he's to young to be attending high-school. Maybe when he gets older he'll become a human.