Languages?

It's a bit weak at first level. I mean, you're just an animal with a iffy natural attack and some cantrips.

MLP unicorns seem pretty versatile with the magic they can create. What if the class schtick was that the unicorn had a 'floating' spell. Essentially the ability to draw any one spell from their choice of the druid (for more standard unicorns) or the sorcerer (for uniponies) spell lists (this choice is made once ever) and cast it, spontaneously, maybe only once or twice a day? Then, to keep players on their toes, you could have the restriction they couldn't cast the same spell in this manner twice in the same month, or there'd be a backfire of some sort?

It builds the idea that unicorns are inherently magical, and it gives the players just a bit more oomph.

Also, I think the Unicorn should be able to qualify for Improved Familiar. I mean, think about it. Pseudodragon is an option.