SYSML17 — The AdjunctProperty is not clearly described

The benefit of the recently introduced Adjunct Property is not clearly stated in the standard. The current description is somewhat baffling and a recent discussion amongst learned members of the SysML RTF revealed further uncertainty.
The standard's development needs to be sensitive to the general criticism that SysML is too complex. Thus language features that are described from their purely functional/implementation point of view neither inform the user community what they are for or, as seems to be the case here, make it clear that this part of the language that is a solution to a problem inherited from UML that modelling tools need to implement and end users need not be too concerned with.
I would also question whether it was correct to change section 11.3.1.1 "Activity" by replacing the BDD representation of activity hierarchy (as per v1.3) with adjunct action properties (introduced in v1.4). Whilst the latter is possible with the AdjunctProperty facility, the prior method, inherited from UML, is still valid. That is, unless the UML activity hierarchy is expressly deprecated from SysML. Even then, it will leave end users with the question of what the additional benefit is of the adjunct property as applied to call behaviour actions.

AdjunctProperty not clearly defined: Resolution provided by other issue resolutions

Split the issue to SYSML17-248 and SYSML17-255.