Should the next version of IFC adopt the latest version of STEP?

Description of the proposal:
IFC2x3 and IFC4 still refer to an older version of STEP. Should IFC5 STEP serialization and schema concepts adopt the new 2016 version?

Describe how it contributes to the objectives set in https://github.com/buildingSMART/NextGen-IFC/wiki/Towards-a-technology-independent-IFC:

What do we win:
1. Referencing
2. UTF-8
3. ...
(need more elaboration)

What do we loose

Schema impact:
Allow external referencing of other IFC files

Instance model impact:
Ability to link multiple instance files

Backwards compatible:
No

Automatic migration possible:
No

Additional implications:

-
Note that not all points need to be satisfied!
Backwards compatibility and file size are not concerns.