I think I can start with what I remember on the issue. I'm completely open to being shown to be wrong or for anyone who can provide better answers.

An interesting part of Irish history is that a huge part of land reform had begun long before independence, which has been seen as some as dampening the agrarian social agitation around the period of independence - which might have been expected to have had an effect on the war. The main period of land reform was centered around the Land Wars, led by the Land League, Michael Davitt and Chales Parnell (who used this fame to later became the great leader of the unsuccessful Home Rule movement). Through boycotting, violence, civil disobedience and mass political agitation a series of Acts between 1870 and independence helped solve the land issue for a majority of tenant farmers. Eventually after a heavy handed response (Coercion acts, involvement of the RIC police force to support the landlords etc.), Westminster with Gladstone's leadership began to try pass a series of acts to bring in rent reforms, rights to buy, compulsory purchase, a land commission and government loans to redistribute the land to change Ireland from a country of tenant farmers to small holders. These schemes continued as far I know after independence though ran into difficulties when DeVelera's Irish government held back annuities amongst other trade disagreements during the Economic War of the nineteen thirties. The overall themes though is that the majority of progress in land reform had already set in place before the war of independence and the tenant farmers were already on their way of gaining ownership of the land - though of course the remaining Landlords will were controversial and embroiled in several parts of the war of Independence.