For example, it doesn't use HTTP/2 (which has a ~100 page RFC and compiles to a ~2MB object file), does not have any load balancing or name resolution engine, and does not handle connection pooling or multiplexing.

Granted, one person's unnecessary is another person's necessary. But since DRPC has a modular design based on small interfaces, many features that are rarely used in gRPC can be excluded and left up to third parties to implement if they want.