Both options have their advantages... and honestly it really comes down to what sort of play style you are wanting from the character.
If you want to hang back and support your allies as a spell caster, straight oracle would be your best bet for a solid 15 caster levels and access to 7th level spells. You can get most of the benefits of the Draconic Bloodline via your Dragon Mystery Revelations as well. You also save yourself a feat by not needing Scaled Disciple
On the other hand, if you see yourself as more of a melee bruiser with spells to back you up, then you will most certainly want to take the dive into Dragon Disciple. An additional +4 Str and +2 Con along with the much higher Natural AC bonus it grants will keep you alive and hitting for much more. However, you will be spending a feat on Scaled Disciple to make your Divine spellcasting Oracle qualify for Dragon Disciple, but you’ll gain some bonus feats from your bloodline, power attack and toughness would both help you out a lot with this route. Also your spells will cap at 6th level and caster level 12.