Thanx for your opinion, helps me to be more confident about this.
Yes, I will definitely give it a try on our test environment first, however I have to somehow choose representative sample out of those 43 K connectors.
Anyway, if you ever want to give it a try, bellow is the SQL Check (MS SQL syntax).
I don't have to explain it to you, as you are expert on data model, but for others - there are columns with information about previous version diagram creted by time aware modeling feature (using xref), as well as there is a info about connected operation (using connectortag).
If you get any results for this query, just search for operation involved and as you select in in Browser use ctrl+U to see how duplicities affect your impact analysis...
SELECT
--top 100
t_diagram.Name as DiagramName
, ver_diagram.Name as PreviousVersionDiagram
, t_diagramobjects.Diagram_ID as StartOnDiagNull
, t_diagramobjects2.Diagram_ID as EndOnDiagNull
, xref.[Description] as XrefDesc
, CASE
WHEN StartObj.Classifier_guid is not null and StartObj.Name is null THEN ':'+StartClassifier.name
WHEN StartObj.Classifier_guid is not null and StartObj.Name is not null THEN StartObj.name+':'+StartClassifier.name
ELSE StartObj.name
END as StartLifeLineName
,t_connector.Name MessageLabel
,t_operation.Name as OperationName
, CASE
WHEN t_object.Classifier_guid is not null and t_object.Name is null THEN ':'+classifier.name
WHEN t_object.Classifier_guid is not null and t_object.Name is not null THEN t_object.name+':'+classifier.name
ELSE t_object.name
END as EndLifeLineName
, t_connector.Connector_ID
, t_connector.SeqNo
, t_connector.Connector_Type
, t_connector.StyleEx
,t_connector.PDATA1
,t_connector.PDATA2
,t_connector.PDATA3
,t_connector.PDATA4
,t_connector.Start_Object_ID
,t_operation.ea_guid as OperationGuid
,t_connector.End_Object_ID
,t_diagram.Diagram_ID
,ver_diagram.Diagram_ID as PDiagram_ID
,t_diagram.Author as DiagramAuthor
,ver_diagram.Author as PDiagramAuthor
,t_diagram.Version
,ver_diagram.[Version] as PVersion
,t_diagram.CreatedDate as DiagramCreatedDate
,ver_diagram.CreatedDate as PDiagramCretedDate
,t_diagram.ModifiedDate as DiagramModifiedDate
FROM t_diagram
LEFT JOIN (select * from t_xref where t_xref.[Type]='reference' and t_xref.Name='Version') as xref on xref.Client=t_diagram.ea_guid
LEFT JOIN t_diagram as ver_diagram on ver_diagram.ea_guid=xref.Supplier
inner join t_connector on t_connector.DiagramID=t_diagram.Diagram_ID
INNER JOIN t_object ON t_object.Object_ID = t_connector.End_Object_ID
INNER JOIN t_object as StartObj on StartObj.Object_ID = t_connector.Start_Object_ID
LEFT JOIN t_object as classifier on t_object.Classifier_guid=classifier.ea_guid
LEFT JOIN t_object as StartClassifier on StartObj.Classifier_guid=StartClassifier.ea_guid
LEFT JOIN t_diagramobjects on t_diagramobjects.Diagram_ID=t_diagram.Diagram_ID and t_diagramobjects.Object_ID=t_connector.Start_Object_ID
LEFT JOIN t_diagramobjects as t_diagramobjects2 on t_diagramobjects2.Diagram_ID=t_diagram.Diagram_ID and t_diagramobjects2.Object_ID=t_connector.End_Object_ID
LEFT JOIN t_connectortag on (t_connector.Connector_ID=t_connectortag.ElementID and t_connectortag.Property='operation_guid')
LEFT JOIN t_operation on t_operation.ea_guid=t_connectortag.value
where 1=1
and t_diagram.diagram_type = 'Sequence'
and (t_diagramobjects.Diagram_ID is null or t_diagramobjects2.Diagram_ID is null)