There are a number of alternatives to ZooKeeper (etcd, Consul, etc). There are a number of systems which specifically require ZooKeeper (Kafka springs to mind).

How plausible would it be to replace hard dependencies on ZooKeeper with a dependency which could be fulfilled by any of the alternatives?

For example, could there be a standard protocol? Could someone implement the ZooKeeper protocol on top of Consul? Could we define a local client API with pluggable implementations for each alternative (like ODBC etc)?

Or are the semantics of the 'alternatives' just too different?