With Zen2 being planned for 7nm it is unlikely to release in 2018, which makes a 12nm (Effectively Gloflo 14nm ++) refresh of Zen a good option.
It really depends on what AMD has done here, whether or not AMD has been able to fix up Ryzen much in silicon and whether or not the new process improves clock speeds or reduces power consumption by a meaningful amount. Even changes that will allow RAM/infinity fabric to run faster would be of huge benefit.
What should be expected is a Bulldozer-Piledriver kind of change, where the node is effectively the same and AMD has the opportunity to improve the design in a few small ways. This design is likely to be more of a polished Zen than a Zen 2.
To make a long story short, there will not be that huge of a leap, 12nm is just a polished 14nm and the Zen core design will not have any transformative changes until Zen 2 on 7nm.