The big players in the market are pushing the SDN approach a lot.
There are several open source projects related to SDN.

As part of the new configuration system we should have a look at the openconfig project (http://openconfig.net) and their vendor neutralconfiguration model. We could expect that most HW manufacturers will support it in the future.

Currently there is no remote interface for configuration.
Looks like a few companies are using (or will use) NETCONF (https://en.m.wikipedia.org/wiki/NETCONF) as protocol together with openconfig.

We could expect a lot of tools around these techniques which then could alsbe be used for VyOS.