Yes, it was directorial license in the sense that it supported a subtheme of GFII: Neri pushing past Rocco, and trying to push past Tom, to become Michael's #2. We see many examples, especially in the penultimate boathouse scene, where Neri leads the discussion about Roth while Rocco stands mute. Then, after Michael humiliates Tom and notes that anyone can be killed, he turns and says "Rocco?" Notice that he doesn't say, "Al?"

But Lou makes a very strong point. It was typical of Michael's character to show the world that he would stop at nothing to get revenge and punish transgressors. And, to make that point, Michael had to be identified in some way with Roth's assassination while he was in FBI's custody, no matter how risky to him. Rocco served that purpose dead or alive. Tom, like Rocco, was high up on the FBI's Corleone Family chart. Tom visited Pentangeli; Pentangeli promptly committed suicide. Another obvious link to Michael--another warning to would-be traitors.