It all really depends on how you define 'realistic'. The Anglo-Irish War was the final conflict that led to Irish success, though even that is debatable as not all players at the time nor now consider a divided Ireland to be a successful outcome. Common Republican thought has Irish history since 1169 consisting of a continuous struggle against the English, with each specific rebellion merely being a singular moment within the larger state of rebellion.

But if you want key revolts then there are three that I would consider close.

• The 1916 Easter Rising was a failure through and through, but Sinn Fein was able to capitalize on the anger over how the leaders were executed to an electoral win in 1918. They then declared an independent Republic and so the Anglo-Irish War began. While the war ultimately led to Home Rule (and in turn to the southern Republic), it was on the heels of the 1916 Rising so depending on you interpretation we could say that 1916 didn't end in defeat but in the Anglo-Irish Treaty of 1921.

• The 1798 Rebellion is impossible to really consider as it was based upon French intervention, but a bad storm in December '98 prevented a French force of 14,000 to land. The rebellion had some victories and the eventual assistance of some French soldier but nothing close to that original force.

• Nine Years' War of 1594-1603 was devastating to the Irish in Ulster due to famine but it also nearly bankrupted the English government. Some choice military blunders led to a mild defeat (mild in that a truce was declared, and the Irish leaders were allowed to live unpunished with only a few caveats). It seems that had the Irish merely waited then the English force would have possibly surrendered or retreated due to starvation and eventual bankruptcy.

However, it is impossible to say really what would have happened in history. Even with the French units or patiences, these past uprisings could have failed all the same.