I think we have to distinguish the popular view from academic history here. There is a consensus that Collins was an effective leader and a promising politician among both historians and the general public. Historians would portray him with more nuance, as one of the key revolutionary leaders rather than as the mastermind he appears in the film. Overall though there isn't much controversy about him.

De Valera has always been contentious. I'm not convinced that the historical consensus was negative. Because he lived so long most historians held off dealing with his legacy until his papers became available. If you read FSL Lyons's Ireland since the Famine which was the standard synthesis until the 1990s, he is critical but not overly negative. There was criticism of the politics of that era , notably economic protectionism and cultural conservatism but these were not De Valera's alone. Popular opinion was very divided Fianna Fáil supporters being very pro-Dev and the rest despising him, particularly because they blamed him for the civil war. The anti De Valera view was expressed by Tim Pat Coogan whose biography was a bestseller but is very biased.

Academics have always had a more nuanced view of De Valera's legacy. That was the way I was taught as far back as 1991 as an undergraduate. There is a generally favourable view of his foreign policy (see Ronan Fanning and Deidre McMahon) and his political acumen (see Dunphy's history of Fianna Fáil). There is also a consensus that his weakest periods were around the Treaty split and his last years as Taoiseach.

The academic view has entered the public consciousness more recently through Diarmaid Ferriter's book Judging Dev and his TV work. Ferriter is a good example of a historian whose personal politics are radically different to his subject but who tries to put De Valera in context. If anything, I think he is too lenient.