While disclosing the companys earnings from last fiscal quarter, Ubisoft were questioned about the troubled launch of Assassin's Creed: Unity. CEO Yves Guillemot said they had to rebuild the engine from scratch in order to make Unity the best it could be, and this process was "painful", as reports Game Informer.
According to Guillemot, Ubisoft has learned a lot from this process, and he believes that "it's going to help the brand shine in the future". Ubisoft didn't, however, say anything about what the troubled launch had cost them in extra work and free DLCs, so this is up for speculation.