I like where this deck is going, may I suggest
Maze's End be included because it allows for multicolored mana to be searched for, as well there are cards like
Dragonlord's Servant and
Dragonspeaker shaman which are a must have! If you're willing to stray from the all dragon path, you could include
birds of paradise, to allow for more mana or even
Opaline unicorn for any color mana. There aren't many low cost dragons so without a doubt there should be lots of ramp cards. Before I ramble too much... hope it helped