As you described already the intent of the File Export Allegro netlist from DxDesigner was a uni-directional interface only into Cadence Allegro for an Expedition Enterprise customer that has a full Central Library environment.
As you point out there is no back-annotation support and there are limitations such as absolutely no future plans to take constraints that have been entered in CES to Allegro.
In terms of other risks, there are no plans in the future to remove the uni-directional interfaces to both Cadence and Zuken environments from our EE flow.
Much thanks! The migration to EE full flow from Allegro full flow isn't easy task in an enterprise environment,there are too barries . I hope a co-exist of Allegro and Expeditionpcb can help this migration safe.