I recently sent an email to the OpenMRS Implements Mailing List describing the evolution of OpenMRS between 2012 and 2015. While writing the email, I thought it might be easier to describe in an image:
Our goal is to get to a UI-less platform (providing API & web services) used by an OpenMRS with a new and agile UI framework that meets or exceeds the needs of existing implementations. Currently, we have several implementations working in the 2.x UI, but the majority of implementations are still using the the 1.x UI. To achieve our goal, we will not only need to reach OpenMRS 2.3 with comparable or greater functionality than OpenMRS 1.9, but also find a way to ease the burden for implementations to migrate from 1.x to 2.x (e.g., migration tools, converting key modules to run in 2.x, possibly find a way to run most 1.x modules within the 2.x framework, etc.).