None of the classes have all their options implemented yet. For instance Warlock only has Pact of the Chain. This isn't so much a flaw as just a fact of early access; they haven't finished designing everything and more will be implemented as time goes on. They want to include everything in the players handbook so even if in the end they have to leave some things out due to budget or time constraints, I think you can be confident that Clerics will get the majority of their domiains by the time full release happens.
