One other thing, are you really sure that Dragon Shamans should get access to Dragon Ally? I mean I'm sure it could be useful if the dragon shaman has money it cannot use any time soon and is stranded on a desert island, but as long as the Dragon Shaman has communications lets say "elsewhere" the Dragon Shaman could just send word to nearby kingdoms th at it is looking to find the services of a dragon for the Dragon's profit. I would honestly either remove that ability altogether and create a capstone that basically does the Greater Dragon Ally once a week because by the time the party is 20th level they are pretty much either overwealthed, or could create a business to generate wealth to find the services of Dragons with practical ease.
Something else I've been kind of wondering about this class lately. Dragon Shamans slowly become more Dragony because they essentially worship dragons and want to become like them. Dragon Disciples somehow become Half Dragons and gain the Dragon type if I remember correctly. So, why don't Dragong Shamans have a Draconic Apotheosis anyways? It makes more sense to me to have something like that rather than Dragon Ally.