As discussed in
CASSANDRA-7510, there is still a gap between when a "node up" or "node added" notification may be sent to native protocol clients (in response to a gossip event) and when the native protocol server is ready to serve requests.
Everything in between the call to StorageService.instance.initServer() and creation of the native server in CassandraDaemon.setup() contributes to this delay, but waiting for Gossip to settle introduces the biggest delay.
We may need to introduce a "STARTING" gossip state for the period inbetween, which is why this is scheduled for 3.0. If there's a better option, though, it may make sense to put this in 2.1.