Motivation
The generic Stunner's domain model, for historical reasons, was being implemented by following the Oryx model (JSON based), in order to reuse some of the already existing capabilities from the legacy (jbpm) process designer. On the other hand, that model is actually not efficient and becomes complex, given the actual Stunner architecture and other layers around.

Goals

The main goal is to improve and refactor the Stunner's generic Domain model and API to allow top level domains (eg: BPMN, DMN) to provide (or update) their domains in a lightway, portable and intuitive way, also by reducing the complexity and imperative code around.

Actions:

• Consider a flat domain, where a Definition (eg: java bean) may have a set of Properties (eg: bean's fields) (no hierarchy from the Stunner core point of view)
• Deprecate core Property Sets (groups of properties)
• Properties can be the ones present on the type itself, but also be inherited or aggregated by other fields
• Support for declaring any field as a Property ( eg: class Task { @Property @FormField String name } )
• Improvements on Property Meta-Types in order to allow proper metadata customizations for any domain object (eg: name)
• Refactor Domain Adapters API 
• Improvements on Client & Server side adapters
• Improvements on the domain's generated code

Next steps

• BPMN2 domain refactorings (see KOGITO-2748)