Almost anything you wish depending on your prejudices.
Here's mine;
Collins survives, although wounded (and livid). Once recovered he brutally supresses the Anti-Treaty forces.
Collins reputation is tarnished amongst revisionist historians by the tactics and policies pursued.
Dev's body is never found.
A Collins-led Free State holds a firmer line in the Boundary Commission negotiations, successfully marrying pragmatism and principle.
Substantial territorial adjustments are highly unlikely as they would only cement the division of the Island.
Instead an 'Tri-Partite Forum' works to address the grievances of communities that feel themselves to be in 'The Wrong Country'.
As a result Northern Ireland and the Free State are less 'Confessional' and inwardly looking triumphalist.
Cross-border and Anglo-Irish co-operation are, of necessity, greater.
The Trade War is avoided, ameliorating the economic distresses of the '30s.
Better relationships lead to the Free State supporting the WAllies in the Second World War.
The Treaty Ports are available for RN use, while Southern Volunteers have an honoured place in the cultural memory of the State.
Southern cities suffer from a number of raids, with many remembering the sterling efforts of the Belfast Fire Brigade to tackle the aftermath of the Dublin Blitz.
Ireland's military modernises and expands, while the island itself plays host to vast numbers of American troops later in the war.
Post War, the Free State benefits from the Marshall Plan, rebuilding its infrastructure and economy.
Some North/South antagonisms remain but the poison has been largely drawn from the wounds of history.
The Free State's major pre-occupation is whether the future lies within the Commonwealth or as part of the emerging European Community.
Ireland's close ties with Britain and the US are seen by many as the reason for the rejection of Membership application in the '60s.
The main political divide is between those who want to 'Cut the Apron Strings', declare a Republic and focus on Europe and those who want to 'Build A Modern Ireland', continue Tri-Partite co-operation and believe 'The Republic' can only come when it consensually embraces the whole Island.
Falkenburg