For starters they will have different healing abilities + synergies with certain creature types.
Ocean healer will have synergies with water and ice type creatures, basically their heals will give certain perks to those creatures, either in how effective they are or other buffs, while also giving resistances when fighting water or ice types to their own creatures.
ooh awesome! I already leaning towards ocean healer cause I always love water/ice types!
And thanks for answering, I know you probably had a blog up somewhere but it's easier to ask then search hehe